HP StorageWorks VLS User Manual
HP StorageWorks VLS and D2D Solutions
Guide
Design Guidelines for Virtual Tape Libraries with
Deduplication and Replication
This document describes the HP StorageWorks VLS and D2D systems and their concepts, including automigration,
deduplication, and replication, to help you define and implement your virtual tape library system. It includes
best practices for working with specific backup applications. This document is intended for use by system
administrators who are experienced with setting up and managing system backups over a SAN.
*AG306-96028*
Part number: AG306-96028
Seventh edition: March 2010
Legal and notice information
© Copyright 2005, 2010 Hewlett-Packard Development Company, L.P.
The information contained herein is subject to change without notice. The only warranties for HP products and services are set
forth in the express warranty statements accompanying such products and services. Nothing herein should be construed as
constituting an additional warranty. HP shall not be liable for technical or editorial errors or omissions contained herein.
Acknowledgements
Microsoft, Windows, Windows XP, and Windows NT are U.S. registered trademarks of Microsoft Corporation.
Oracle is a registered US trademark of Oracle Corporation, Redwood City, California.
Contents
1 Introduction ..................................................................................... 13
2 Concepts ........................................................................................ 15
Disk-based Backup and Virtual Tape Libraries ............................................................................... 15
Problems Addressed by Virtual Tape Libraries ......................................................................... 15
Integration of Disk in Data Protection Processes ...................................................................... 15
Where Virtual Tape Fits in the Big Picture ............................................................................... 16
HP VLS and D2D Portfolio ................................................................................................... 16
Typical VLS Environments ..................................................................................................... 17
Typical D2D Environments ................................................................................................... 17
What are the Alternatives? .................................................................................................. 18
Physical Tape .............................................................................................................. 18
NAS .......................................................................................................................... 18
Application-based Disk Backup ...................................................................................... 18
Business Copy ............................................................................................................. 19
Deduplication ........................................................................................................................... 20
Introduction ....................................................................................................................... 20
HP StorageWorks Deduplication Solutions ............................................................................. 20
Deduplication Ratios ........................................................................................................... 21
Target-based Deduplication ................................................................................................. 22
Tape Oversubscription ........................................................................................................ 23
Replication ............................................................................................................................... 23
Introduction to Replication ................................................................................................... 23
HP StorageWorks Replication Solutions ................................................................................. 24
Replication Deployment Options ........................................................................................... 26
Backup Application Interaction with Replication ...................................................................... 28
Replication Limitations ......................................................................................................... 29
3 Backup Solution Design Considerations ............................................... 31
Analyze the Existing Environment ................................................................................................ 31
Consider How you Want to Back Up your Data to the VLS or D2D ........................................... 31
Consider How you Want to Copy the Backup Data to an Off-site Location ................................. 33
Consider Speed and Ease of the Restore as well as the Backup ................................................ 33
Single Library vs. Multiple Libraries ............................................................................................. 33
Single Library .................................................................................................................... 33
Benefits of Single Library Systems ................................................................................... 34
Considerations for Single Library Systems ........................................................................ 34
Multiple Library .................................................................................................................. 35
Benefits of Multiple Library Systems ................................................................................ 35
Multiplexing, Multistreaming, and Multipathing ............................................................................ 36
Multiplexing ...................................................................................................................... 36
Multistreaming ................................................................................................................... 36
Multipathing ...................................................................................................................... 36
Blocksize and Transfer Size ........................................................................................................ 37
HP StorageWorks VLS and D2D Solutions Guide 3
LAN-free Backups ..................................................................................................................... 37
Retention Planning .................................................................................................................... 37
Future Data Growth ................................................................................................................... 38
Considerations for Copies .......................................................................................................... 38
Copy to Physical Tape through the Backup Application ............................................................ 39
Media Server Considerations ........................................................................................ 40
Benefits of Copying to Physical Tape through the Backup Application ................................. 40
Considerations for Copying to Physical Tape through the Backup Application ...................... 41
Copy to Tape using VLS Automigration .................................................................................. 41
Benefits of Echo Copy .................................................................................................. 42
Considerations of Echo Copy ........................................................................................ 42
Copy to Tape using D2D Tape Offload ................................................................................. 43
Copy to Remote Disk Backup Device using Replication ............................................................ 43
Benefits of Replication .................................................................................................. 44
Considerations of Replication ........................................................................................ 44
Creating Archive Tapes from the Replication Target ................................................................. 44
Considerations for Restores ........................................................................................................ 44
Restoring from Disk Backup Device ....................................................................................... 45
Restoring from Backup Application-created Tape Copy ............................................................ 45
Restoring from the Replication Target ..................................................................................... 45
Performance Bottleneck Identification ........................................................................................... 45
Backup SAN Design Guidelines .................................................................................................. 46
General SAN Design Considerations .................................................................................... 46
SAN Zoning ...................................................................................................................... 46
Operating System Tape Configuration ................................................................................... 47
LUN Masking and Mapping ................................................................................................ 49
Backup Application Basic Guidelines .......................................................................................... 50
HP Data Protector Application Overview ............................................................................... 51
Symantec NetBackup Application Overview .......................................................................... 51
IBM TSM Application Overview ........................................................................................... 52
EMC NetWorker Application Overview ................................................................................. 53
4 D2D Systems ................................................................................... 55
D2D Devices ............................................................................................................................ 55
D2D Defined ..................................................................................................................... 55
D2D Technical Specifications ......................................................................................... 56
D2D Design Considerations ................................................................................................. 56
D2D Port Optimization ................................................................................................. 56
Multiple Backup Streams ............................................................................................... 57
Disable Backup Application Verify Pass .......................................................................... 58
Tape Copy or Offload Performance ................................................................................ 58
Tape Library Emulation ................................................................................................. 59
Optimizing Rotation Scheme to Reduce Housekeeping ...................................................... 59
D2D Blueprints ................................................................................................................... 60
Single Site Cost Effective Backup Device Consolidation ..................................................... 60
Large SME Site Consolidation Requiring Fibre Channel Shared Devices .............................. 61
Multi-site Small Business Disaster Recovery Solution .......................................................... 63
Introduction to VMWare Terminology ............................................................................. 65
Using D2D in Simple VMWare Environments with ESXi ..................................................... 66
Using D2D in VMWare Environments with ESX4 and VMWare Consolidated Backup ........... 66
Using D2D in larger VMWare environments with HP Data Protector Zero Downtime Backup
with Instant Recovery (ZDB + IR) .................................................................................... 67
D2D Dynamic Deduplication ...................................................................................................... 69
How it Works .................................................................................................................... 69
4
Dynamic Deduplication Implementation ................................................................................. 70
Restoring Data ................................................................................................................... 71
Housekeeping .................................................................................................................... 72
D2D Replication ....................................................................................................................... 73
How it Works .................................................................................................................... 73
D2D Replication Implementation ........................................................................................... 73
Licensing .................................................................................................................... 74
Implementing the Initialization Process ............................................................................ 74
Replication Setup ......................................................................................................... 76
Reporting ................................................................................................................... 82
Design Considerations ........................................................................................................ 84
Link Sizing .................................................................................................................. 84
Telco Provisioning — Overview of Inter-Site Links .............................................................. 90
Some Idea of Telco Costs .............................................................................................. 92
Telco Terminology and Branding for WAN Services ......................................................... 93
D2D Replication Data Recovery Options ............................................................................... 95
Restore Directly from the D2D Target Device .................................................................... 95
Reverse Replication on the D2D ..................................................................................... 95
Reverse Tape Initialization on the D2D ............................................................................ 98
Creating Archive Tapes from the Target ........................................................................... 99
5 Virtual Library Systems .................................................................... 101
VLS Devices ........................................................................................................................... 101
VLS Defined ..................................................................................................................... 101
Prime Environments .................................................................................................... 102
VLS Benefits .............................................................................................................. 102
VLS9000–series Configurations ................................................................................... 103
VLS Technical Specifications ........................................................................................ 104
How it Works .................................................................................................................. 111
VLS Scalability .......................................................................................................... 111
VLS Automatic Performance Load Balancing .................................................................. 113
VLS Warm Failover .................................................................................................... 114
Implementation ................................................................................................................ 115
Device Configuration Preparation ................................................................................. 115
Capacity Licensing ..................................................................................................... 117
Virtual Libraries/drives/cartridge Configuration ............................................................. 118
EVA Preparation ........................................................................................................ 119
Storage Pooling ......................................................................................................... 121
VLS Design Considerations ................................................................................................ 123
VLS Sizing ................................................................................................................ 123
VLS Blueprints .................................................................................................................. 127
Reduce Backup Window (No Deduplication) ................................................................. 127
Large Scale Backup Consolidation (No Deduplication) .................................................... 128
Managing Data Retention and Reducing Backup Storage Costs ....................................... 129
Full Enterprise Backup and Disaster Recovery Capability ................................................. 130
Multi-data Center Replication to a Common Disaster Recovery Site ................................... 132
VMWare Backup Environment with ESXi. ....................................................................... 133
VMWare Backup Environment with ESX4 and VCB-based Backups ................................... 134
Larger VMWare Environment with ESX4 and HP Data Protector ZDB IR Integration with
VMWare Consolidated Backup ................................................................................... 136
Large Enterprise Cross-site Backup with Deduplication and Inbuilt Disaster Recovery ........... 138
Combining D2D and VLS in an End-to-end Solution for ROBO/Regional DCs and Main Data
Center using HP Data Protector .................................................................................... 139
VLS Automigration .................................................................................................................. 140
HP StorageWorks VLS and D2D Solutions Guide 5
Echo Copy Concepts ........................................................................................................ 141
Implementation ................................................................................................................ 141
Echo Copy Pools ........................................................................................................ 141
Automigration Policy .................................................................................................. 142
Automigration Setup ................................................................................................... 143
Design Considerations ...................................................................................................... 145
Automigration Use Models .......................................................................................... 145
Sizing the Tape Library ............................................................................................... 147
Restoring from Automigration Media ................................................................................... 148
VLS Accelerated Deduplication ................................................................................................. 148
How it Works .................................................................................................................. 149
Accelerated Deduplication Implementation .......................................................................... 152
Supported Backup Applications and Data Types ............................................................ 153
Deduplication Preparation ........................................................................................... 153
Licensing .................................................................................................................. 154
Migrating your Existing Backup Data ............................................................................ 155
Configuration and Reporting ....................................................................................... 155
Handling the Device Out of Capacity Condition ............................................................ 156
Design Considerations ...................................................................................................... 157
Performance .............................................................................................................. 157
Capacity Sizing ......................................................................................................... 158
Node Oversubscription .............................................................................................. 158
Optimum Record Sizing .............................................................................................. 159
Optimizing File Server Deduplication ........................................................................... 159
Media Management .................................................................................................. 160
Client and Backup Job Naming ................................................................................... 160
Disabling Deduplication on Specific Backup Policies ....................................................... 161
VLS Replication ....................................................................................................................... 161
How it Works .................................................................................................................. 161
Replication of Incremental Backups ............................................................................... 163
Multi-node Replication Scaling .................................................................................... 164
VLS Replication Implementation .......................................................................................... 164
Licensing .................................................................................................................. 164
Replication Preparation ............................................................................................... 165
Replication Setup ....................................................................................................... 166
Implementing the Initialization Process .......................................................................... 172
Reporting ................................................................................................................. 176
Design Considerations ...................................................................................................... 180
Advanced Replication Job Control ................................................................................ 180
Link Sizing ................................................................................................................ 182
Device Sizing ............................................................................................................ 187
VLS Replication Data Recovery Options ............................................................................... 187
Restore Directly from the VLS Target Device .................................................................... 187
Restore the VLS over the LAN/WAN ............................................................................ 189
Rebuilding Source Device and Re-establishing Replication ............................................... 190
Creating Archive Tapes from the Target ......................................................................... 190
VLS Non-deduplicated Replication ............................................................................................ 192
Replicating a Subset of Virtual Cartridges - a Use Case ......................................................... 193
Detailed Backup Application Guidelines for VLS ......................................................................... 194
HP Data Protector ............................................................................................................. 194
Data Protector General Guidelines ............................................................................... 194
Data Protector Deduplication Guidelines ....................................................................... 195
Data Protector Import Example Script ............................................................................ 196
Symantec NetBackup ........................................................................................................ 197
NetBackup General Guidelines ................................................................................... 197
6
NetBackup Deduplication Guidelines ........................................................................... 198
NetBackup Import Example Script ................................................................................ 198
IBM TSM ......................................................................................................................... 199
TSM General Guidelines ............................................................................................ 199
TSM Deduplication Guidelines .................................................................................... 200
TSM Useful Queries ................................................................................................... 203
EMC NetWorker .............................................................................................................. 204
Networker General Guidelines .................................................................................... 204
Networker Deduplication Guidelines ............................................................................ 206
6 Support and Other Resources .......................................................... 209
Related Information ................................................................................................................. 209
Documents ...................................................................................................................... 209
Websites ......................................................................................................................... 209
Contacting HP ........................................................................................................................ 209
Before you contact HP ....................................................................................................... 209
HP contact information ...................................................................................................... 210
Subscription Service ................................................................................................................ 210
Document Conventions and Symbols ......................................................................................... 210
Glossary .......................................................................................... 213
Index ............................................................................................... 215
HP StorageWorks VLS and D2D Solutions Guide 7
Figures
11
12
Common Backup Technologies ................................................................................. 161
HP Virtual Tape Library Product Range ....................................................................... 172
Basic Write-to-disk Setup ......................................................................................... 193
Unique Backup Data ............................................................................................... 204
Enterprise Deployment with Small and Large Remote and Branch Offices ........................ 245
Remote Site Data Protection Before Replication ........................................................... 256
Remote Site Data Protection Using Replication ............................................................ 257
Replication Configuration Options ............................................................................. 278
Presenting the Replication Target to a Different Backup Application ................................ 289
Backup to the VLS in a LAN/SAN Hybrid Environment ................................................. 3210
Backup to VLS in a Simple Deployment (VLS9000–series with One Shared Library
Shown) .................................................................................................................. 34
Backup to VLS in a Simple Deployment (VLS9000–series with Four Dedicated Libraries
Shown) .................................................................................................................. 35
Writing to Tape in a LAN/SAN Hybrid Environment .................................................... 4013
Echo Copy is Managed through Automigration ........................................................... 4214
Virtual Tape Environment ......................................................................................... 5015
TSM LAN-based backups ......................................................................................... 5216
TSM LAN-free backups ............................................................................................ 5317
Single Site Backup Consolidation using iSCSI ............................................................. 6118
Large SME Site Consolidation Requiring FC Shared Devices ......................................... 6219
Multi-site Small Business Automated Disaster Recovery Solution ..................................... 6320
Multi-site Small Business Automated Disaster Recovery Solution with no Physical Tape ...... 6421
VMWare Infrastructure Environment ........................................................................... 6522
Using D2D in VMWare Environment with ESX4 and VCB Backup for SAN-based
23
Backup .................................................................................................................. 66
Using D2D in a VMWare Environment with ESX4 and HP Data Protector ZDB IR ............. 6824
Hash-based Chunking ............................................................................................. 7025
D2D Configuration .................................................................................................. 7126
Dynamic Deduplication Ratio .................................................................................... 7127
Restoring from a Recipe File ..................................................................................... 7228
Options for Initialization the Initial Data ..................................................................... 7429
Slot Mappings ........................................................................................................ 7730
8
Example Schematic ................................................................................................. 7831
Example 1: 100 GB Virtual Cartridge Replication over a 2 Mb/sec Link with 100%
32
Bandwidth Utilization .............................................................................................. 85
Example 2: 100 GB Virtual Cartridge Replication over a 2 Mb/sec Link with 25%
33
Bandwidth Utilization .............................................................................................. 86
Example 3: 500 GB Virtual Cartridge Replication over a 2 Mbit/sec Link ...................... 8634
Example 4: 500 GB Virtual Cartridge Replication over a 10 Mbit/sec Link .................... 8735
Many-to-One Example using Mixed WAN Link Speeds ................................................ 8836
A Basic WAN using MPLS ....................................................................................... 9237
Recovery Options — Data Center Rebuild and Reverse Replication ................................ 9538
Recovery Options — Physical Tape ........................................................................... 9939
Creating Archive Tapes from the Target .................................................................... 10040
7.5 TB System with Expansion Disk Array Enclosures .................................................. 10341
Full VLS9000 System ............................................................................................. 10442
Internal Architecture of the VLS (VLS9000 Shown) ..................................................... 11243
Virtual Drives across Multiple Nodes ....................................................................... 11344
Storage Pool Load Balancing on the VLS .................................................................. 11445
VLS12000 EVA Gateway Connected to an EVA ........................................................ 12046
Single vs. Multiple Storage Pool Considerations ........................................................ 12247
VLS9000 Partially Populated Storage Pools ............................................................... 12348
Testing Backups to Tape vs. Backups to a VLS ........................................................... 12649
Using VLS to Reduce the Backup Window ................................................................ 12750
Using VLS for Large Scale Consolidation .................................................................. 12851
Using VLS to Manage Data Retention and Reduce Backup Storage Costs ..................... 13052
Using VLS with Full Enterprise Backup and Disaster Recovery Capability ....................... 13153
Using VLS with Multi-data Center Replication to a Common Disaster Recovery Site ........ 13254
Using VLS with VMWare using Backup Agents ......................................................... 13455
Using VLS with VMWare using VCB ........................................................................ 13556
Using VLS in Larger VMWare Environments with HP Data Protector ZDB IR Backup ........ 13757
Using VLS in Enterprise Cross Site Backup Scenarios .................................................. 13858
Using D2D and VLS in ROBO/RDC/MDC Environments ............................................ 14059
Linked Media ....................................................................................................... 14260
Automigration Policy Details ................................................................................... 14261
Automigration Media Life Cycle .............................................................................. 14462
Multiple Virtual Libraries ........................................................................................ 14663
Shared Virtual Library ............................................................................................ 14764
Steps of Accelerated deduplication ........................................................................ 14965
HP StorageWorks VLS and D2D Solutions Guide 9
Backup Analysis ................................................................................................... 15066
Physical versus Logical Data ................................................................................... 15067
Backup Sessions with Duplicate and Unique Data .................................................... 15268
VLS9000 and VLS12000 node oversubscription ....................................................... 15869
How Replication Fits into the Deduplication Architecture ............................................. 16270
The Replication Sequence ...................................................................................... 16371
Replication Scaling ............................................................................................... 16472
Preparing the Network Connection for Replication in a VLS ........................................ 16673
VLS Replication by Numbers ................................................................................... 16774
VLS Initialization using Physical Tape ....................................................................... 17375
VLS Initialization using the WAN ............................................................................ 17576
VLS Initialization by Co-location .............................................................................. 17677
Dividing the Backup Jobs by Priority Level ................................................................. 18178
VLS Sizing Example 1 ........................................................................................... 18379
VLS Sizing Example 2 ........................................................................................... 18480
VLS Sizing Example 3 ........................................................................................... 18581
VLS Sizing Example 4 ........................................................................................... 18682
VLS Recovery Options for a Data Center Rebuild ....................................................... 18883
Data Recovery from the Target VLS .......................................................................... 18984
Creating Archive Tapes from the VLS ....................................................................... 19185
Site-to-site Replication ............................................................................................ 19386
10
Tables
10
13
VLS Compared to Application-based Write-to-disk ....................................................... 191
HP Deduplication Solutions ...................................................................................... 212
1 TB File Server Backup ........................................................................................... 223
Deduplication Ratio Impact ...................................................................................... 224
Estimated Time to Replicate Data for a 1 TB Backup Environment at 2:1 ......................... 265
D2D Technical Specifications .................................................................................... 566
Sample Initialization and Replication Times ................................................................ 897
Telco Prices for a 3-year Contract Including Installation (No Existing Links in Place) .......... 928
Prices of a Major US Telco for HP Facilities in the Houston, Texas Area .......................... 939
Prices of a Telco Provider in Colorado for HP Sites Located around 250 km (175 miles)
Apart .................................................................................................................... 93
Prices for Point to Point Connects from HP Facilities based in Singapore .......................... 9311
Sample British Telcom Services and Speeds ................................................................ 9412
VLS9000–series Multi-node Maximum Capacity by Configuration with 20–port Connectivity
Kit and 40 TB Arrays (2:1 Compression, Non-deduplication) ...................................... 104
VLS9000–series Multi-node Maximum Capacity by Configuration with 32–port Connectivity
14
Kit and 40 TB Arrays (2:1 Compression, Non-deduplication) ...................................... 105
VLS9000–series Multi-node Maximum Capacity by Configuration with Two 32–port
15
Connectivity Kits and 40 TB Arrays (2:1 Compression, Non-deduplication) ................... 105
VLS9000–series Backup Performance by Configuration .............................................. 10616
VLS6000–series Technical Specifications .................................................................. 10617
VLS6000–series Performance by Configuration, 4 GB Models .................................... 10718
VLS12000 EVA Gateway Technical Specifications ..................................................... 10819
VLS12000 EVA Gateway Backup Throughput using Deduplication .............................. 10820
VLS12000 EVA Gateway Backup Throughput without Deduplication ............................ 10921
Base Capacity License by VLS Model ...................................................................... 11722
Adding Capacity Beyond the Base Configuration ...................................................... 11723
Required Deduplication Licenses by Platform ............................................................. 15524
VLS9000 and VLS12000 Node Oversubscription Options ......................................... 15825
Network Latency ................................................................................................... 18126
Summary of the Calculations Involved in the Sizing Examples ..................................... 18527
Recommended Settings for each TSM Server's dsmserv.opt File or Storage Agent’s
28
dsmsta.opt ........................................................................................................... 199
HP StorageWorks VLS and D2D Solutions Guide 11
Recommended Settings for each Backup-archive Client's dsm.sys File (dsm.opt File for
29
Windows) ............................................................................................................ 200
Document conventions ........................................................................................... 21030
12
1 Introduction
Welcome to virtual tape libraries. This guide describes the HP StorageWorks VLS and D2D systems
and their concepts, including automigration, deduplication, and replication, to help you define and
implement your virtual tape library system. It includes best practices for working with specific backup
applications.
Although every user environment and every user’s goals are different, there are basic considerations
that can help you use the VLS or D2D effectively in your environment. The VLS and D2D are two
powerful and flexible families of devices. Because they can be productively used in so many ways,
there is no “best” configuration. But by asking yourself the questions and following the parameters
outlined in this guide, you can define and implement a system that is best for your particular
environment and applications.
Before proceeding, make sure you are familiar with the items below.
• Tape backup technologies, tape libraries, and backup software.
• SAN environments.
• Fibre Channel technology.
See the Glossary for the definition of acronyms and specific terms.
NOTE:
This guide replaces the
Deduplication and replication solutions guide
guide
.
HP StorageWorks Virtual Library System Solutions Guide
, and the
, the
HP StorageWorks
HP StorageWorks Deduplication solutions
HP StorageWorks VLS and D2D Solutions Guide 13
Introduction14
2 Concepts
Disk-based Backup and Virtual Tape Libraries
Problems Addressed by Virtual Tape Libraries
You can optimize your backup environment with VLS and D2D if you are:
• Not meeting backup windows due to slow servers.
• Not consistently streaming your tape drives.
• Dealing with restore problems caused by interleaving.
• Performing many restores (such as single file or small database restores).
• Backing up data that has a short life.
• Having issues with backup reliability.
• Using snapshot and clone technology for non-critical data (which makes the storage inappropriately
expensive for the nature of the data).
• Looking to deemphasize tape in your environment. Bear in mind that removable media remains
valuable in its own right and for particular purposes such as site protection and protection from
malicious attack (e.g., viruses and hackers), data distribution, data copy, archive, and regulatory
compliance.
• Improving media management. You can keep incremental backups on virtual tape and send full
backups straight to tape.
Integration of Disk in Data Protection Processes
Globalization, 24x7 environments, and consolidation are driving more rigorous data protection
requirements. To address these requirements, disk is frequently introduced into the backup process.
In disk solutions, data is backed up from an application server (disk) over a dedicated SAN to a
disk-based system and from there to a traditional tape library. This provides enhanced solutions for
slow servers, single-file restores, and perishable data.
One of the particular benefits of the VLS and D2D is that they make a disk array look to your backup
server like a tape library. Implementation requires no new software and no significant redesign of
your backup processes. On the VLS300 and VLS12000 Gateways, because they are attached to an
EVA, the existing Fibre Channel infrastructure and management framework is used and there is no
new management server required.
NOTE:
Tape holds its value for ease of vaulting, economical long-term retention, and immutability (with
WORM). It is the last step in your data’s storage cycle.
HP StorageWorks VLS and D2D Solutions Guide 15
Where Virtual Tape Fits in the Big Picture
Virtual libraries are not necessarily the only piece of your backup plans, but they can be an integral
piece of a successful solution. Figure 1 illustrates the common backup technologies and their relative
benefits and costs.
Figure 1 Common Backup Technologies
.
See What are the Alternatives? for more discussion of the other potential players in your backup
environment.
HP VLS and D2D Portfolio
HP offers a wide range of disk-based backup products to help organizations meet their data protection
challenges. Moving the front line of data protection from tape to disk reduces administrative overhead;
daily backups are entirely automated and involve no tape handling to provide better backup reliability
and less worry.
The entry level D2D100 series Backup System meets the needs of small businesses as a low-cost
solution that does not incorporate deduplication technology. The D2D2500 is well suited for remote
and branch offices and small IT environments, while the more powerful D2D4000 and D2D4100 are
designed for medium-sized companies and small data centers. The D2D2500, D2D4000 and
D2D4100 products include HP Dynamic deduplication, which provides low cost and flexibility to
meet the needs of smaller IT environments.
HP Virtual Library Systems are known for their easy integration, simple management, performance
and capacity scalability, and fast restores. The VLS6000, VLS9000 and VLS12000 EVA Gateway
are designed for medium to large-scale enterprises. They feature Accelerated deduplication, available
by license, to deliver the best backup performance and scalability for high availability data center
environments.
Concepts16
Figure 2 HP Virtual Tape Library Product Range
.
Typical VLS Environments
In a typical enterprise backup environment, there are multiple application servers backing up data to
a shared tape library on the SAN. Each application server contains a remote backup agent that sends
the data from the application server over the SAN fabric to a tape drive in the tape library. However,
because backup over the SAN is single-threaded (a single host is backing up to a single tape drive),
the speed of any single backup can be limited. This is particularly true when the environment has
high-speed tape drives such as Ultrium 2 or Ultrium 3. The hosts simply cannot keep the drives streaming
at capacity.
NOTE:
HP Ultrium drives will adjust the tape speed to match the data stream to prevent “back-hitching.”
However, the tape drive is still not operating at optimal performance and cannot share bandwidth
with another backup job.
Enterprise data centers with slow SAN hosts in the environment may be unable to utilize the full
performance of high-speed tape drives. Also, shared tape libraries on the SAN can be difficult to
configure both in the hardware and in the data protection software.
Typical D2D Environments
In a typical entry-level or mid-range backup environment, the backup application is performing LAN
backups to a dedicated (non-shared) backup target such as a tape library connected to the single
backup server. Multiple instances of the backup application will generally each require their own
dedicated backup target. These environments may also be remote branch offices, each with their own
local backup application.
As with the VLS, the backup speed of a single host backing up to a single tape drive is normally
limited by the host (which cannot stream high-speed tape drives such as LTO), so currently tape backups
use multiplexing to interleave multiple hosts’ backups together into a single tape drive impacting
HP StorageWorks VLS and D2D Solutions Guide 17
restore performance. The addition of a D2D device to these environments allows de-multiplexing of
the backups so that restore performance is improved, the deduplication allows for a longer retention
time on disk without needing significantly higher disk capacities, and the deduplication-enabled
replication allows cost-effective off-site copying of the backups for disaster protection.
What are the Alternatives?
Alternatives to virtual tape solutions include:
• Physical Tape
• NAS (network attached storage)
• Application-based Disk Backup (disk to disk, backup to disk, disk to disk to tape)
• Business Copy (snapshot and clone solutions)
Physical Tape
Tape is the foundation for data protection and should be a part of most data protection solutions
(except those with highly perishable data). Consider a direct-to-tape scheme if:
• You are doing large image backups (i.e., databases), or
• Your servers can stream the tape drives.
and
• You do not need fast single file restore, or
• Your current backup window is not strained.
NAS
An alternative to a virtual library is a NAS device acting as a backup target (via NFS or CIFS network
file system protocols). However, this protocol has significant performance and scaling limitations;
writing backups over TCP/IP and NFS/CIFS to the NAS target uses much more CPU on the backup
infrastructure compared to Fibre Channel SAN. In addition, a NAS mount point does not scale to the
size of an enterprise virtual tape library. For example, a VLS can present a single virtual library target
containing multiple petabytes of tape capacity with all backup jobs configured to use the one common
shared high-performance high-capacity VLS backup device.
Consider a NAS target if you:
• Do not have high performance requirements.
• Do not want to run SAN backups.
• Do not need the backup target to significantly scale capacity or performance.
• Want to run Data Protector “virtual full backups.”
Application-based Disk Backup
Utilizing the file library functionality of backup applications is good for small or isolated jobs. When
a large-scale implementation is required, virtual tape offers a more easily managed, higher performing
solution. Consider a file library system if:
• The application is in a LAN or LAN/SAN hybrid configuration.
• Fewer than four servers write data to secondary disk storage.
• You can redeploy existing arrays as secondary disk storage.
• Your environment is static.
Concepts18
Figure 3 Basic Write-to-disk Setup
.
Table 1 VLS Compared to Application-based Write-to-disk
Write-to-diskVirtual tape devices
Setup and management complexity
Data compression
Performance
Cost
Business Copy
Using a business-copy solution (array snapshots/clones) generally involves a much higher cost than
a virtual library system. You might, however, implement such a solution if:
• Virtually instant recovery is critical.
• You need to leverage a high-availability investment.
• You are doing image recovery rather than file recovery.
• You need a zero downtime solution.
Sets up just like a physical tape library.
Software or hardware enabled (software
compression generally decreases performance).
Hardware devices are tuned for sequential
read and write operations.
More expensive acquisition cost.
Backup software licenses as if physical
library or per TB.
Storage efficiency gained through
compression.
Lower management overhead.
Requires configuration of RAID groups,
LUNs, volumes, and file systems.
No device-side data compression available.
Performance dependent on target array or
server.
Free or licensed per TB in most backup
applications.
Higher management overhead.
HP StorageWorks VLS and D2D Solutions Guide 19
Deduplication
Introduction
In recent years, the amount of data that companies produce has been steadily increasing. To comply
with government regulations, or simply for disaster recovery and archival purposes, companies must
retain more and more data. Consequently, the costs associated with data storage – labor, power,
cooling, floor space, transportation of physical media – have all risen. Virtual tape libraries have
become a cornerstone in modern data protection strategy due to their many benefits; chief among
these is cost. The list of virtual tape benefits also includes seamless integration into existing backup
solutions, improved SAN backup performance, and faster single file restores than those performed
with physical tape.
Deduplication, one of the most significant storage enhancements in recent years, promises to reshape
future data protection and disaster recovery solutions. This technology is ideal for virtual tape libraries.
Deduplication technology references blocks of data that have been previously stored, and only stores
new backup data that is unique. Data that is not unique is replaced with a pointer to the location of
the original data. Because there is often a great deal of duplicate data present from one backup
session to the next, disk space is consumed by similar or identical iterations of data. Deduplication
greatly improves storage efficiency by only storing an instance of data once, while still allowing
backup streams to be restored as if they had been retained in their entirety. See Figure 4.
DescriptionItem
Data from the first backup stream is stored to disk.1
Duplicate data (in blue) as well as unique data (in red) in a second backup stream is identified.2
Duplicate data in the second backup stream is eliminated.3
Unique data in the second backup stream is stored to disk.4
Figure 4 Unique Backup Data
.
HP StorageWorks Deduplication Solutions
HP offers two deduplication technologies: HP Accelerated deduplication, a licensed feature available
with HP StorageWorks Virtual Library Systems (VLS), and HP Dynamic deduplication, an integrated
feature with HP StorageWorks D2D Backup System. Both HP deduplication solutions offer the following
benefits:
• Longer retention of data.
• Faster, less expensive recoveries and improved service levels.
• Fewer resources consumed, reducing operational costs.
Concepts20
• Completely transparent to host.
• No data is lost – backup streams can be fully restored.
• Block or chunk level deduplication, providing greater reduction of data.
• Even greater reduction of data when combined with traditional data compression.
HP Accelerated deduplication and HP Dynamic deduplication are designed to meet different needs,
as shown in Table 2.
Table 2 HP Deduplication Solutions
HP Dynamic deduplicationHP Accelerated deduplication
• Intended for enterprise users.
• Uses object-level differencing technology.
• Fastest possible backup performance.
• Fastest restores.
• Most scalable solution in terms of performance and
capacity.
• Potentially higher deduplication ratios.
See VLS Accelerated Deduplication and D2D Dynamic Deduplication for more details on HP
deduplication technologies.
Deduplication Ratios
The storage capacity saved by deduplication is typically expressed as a ratio, where the sum of all
pre-deduplicated backup data is compared with the actual amount of storage the deduplicated data
requires. For example, a 10:1 ratio means that ten times more data is being stored than the actual
physical space it would require.
The most significant factors affecting the deduplication ratio are:
• How long the data is retained.
• How much the data changes between backups.
Table 3 provides an example of storage savings achieved with deduplication. However, many factors
influence how much storage is saved in your specific environment. Based on the retention policies
shown below, six months of data without deduplication requires 12.75 TB of disk space. With
deduplication, six months of data requires less than 1.25 TB of storage.
• Intended for mid-sized enterprise and remote office
users.
• Uses hash-based chunking technology.
• Integrated deduplication.
• Lower cost and a smaller RAM footprint.
• Backup application and data type independence
for maximum flexibility.
Retention policy:
• 1 week, 5 daily incremental backups
• 6 months, 25 weekly full backups
Data parameters:
• Data compression rate = 2:1
• Daily change rate = 1% (10% of data in 10% of files)
HP StorageWorks VLS and D2D Solutions Guide 21
Table 3 1 TB File Server Backup
...
Approximately 11:1 reduction in data stored
Data stored with deduplicationData stored normally
500 GB500 GB1st daily full backup
5 GB50 GB1st daily incremental backup
5 GB50 GB2nd daily incremental backup
5 GB50 GB3rd daily incremental backup
5 GB50 GB4th daily incremental backup
5 GB50 GB5th daily incremental backup
25 GB500 GB2nd weekly full backup
25 GB500 GB3rd weekly full backup
25 GB500 GB25th weekly full backup
1,125 GB12,750 GBTotal
Table 4 is an example that may not reflect the savings that all environments achieve using deduplication.
As shown, deduplication ratios depend on the backup policy and on the percentage of change
between backups.
Table 4 Deduplication Ratio Impact
Backup policyDaily
change rate
*4 months = 5 daily + 17 weekly backups
See Performance for additional information on optimizing your deduplication performance.
Target-based Deduplication
VLS and D2D deduplication is target-based; the process is running transparently inside the hardware.
This means that when the data is read (by copying to physical tape, restoring a backup, etc.), the
device rebuilds the data. The data that is read is identical to the data that was originally written (like
tape drive compression); there are no pointers in the read data.
Daily incremental (10%) and weekly fullDaily full and weekly full
1 year6 months4 months*1 year6 months4 months*
23:116:112:125:119:115:10.5%
15:111:110:116:113:112:11.0%
9:17:17:19:19:18:12.0%
Concepts22
Tape Oversubscription
Deduplication requires more virtual tape capacity than physical disk; this is sometimes called tape
oversubscription. The purpose of deduplication is to reduce the amount of disk required to store
multiple generations of backups. Be sure to create enough virtual tape capacity to contain your entire
retention policy, and the amount of physical disk will be much less capacity due to deduplication.
For example, if you are backing up 50 TB per week and retaining four weeks, you need to create
enough virtual tape capacity (after compression) to store 200 TB of backups. If you have 2:1
compression, you must create 100 TB of virtual tape capacity to hold the four weeks of backup data.
Given deduplication across the four weeks of backup versions, the amount of physical disk required
for this 100 TB of virtual tape would be significantly less.
NOTE:
Do not create too much virtual tape capacity or your backup application may be set to prefer to use
blank tapes instead of recycling older tapes. You would likely run out of disk space because the older
backups are not being recycled/overwritten and thus the disk space used by these old backups is not
freed up. As in the example above, you should create enough virtual tape capacity to hold backups
for your entire retention policy but no more.
Replication
Introduction to Replication
Deduplication can automate the off-site process and enable disaster recovery by providing site to site
deduplication-enabled replication at a lower cost. Because deduplication knows what data has
changed at a block or byte level, replication becomes more intelligent and transfers only the changed
data instead of the complete data set. This saves time and replication bandwidth, and is one of the
most attractive features that deduplication offers. Replication enables better disaster tolerance with
higher reliability but without the operational costs associated with transporting data off-site on physical
tape.
You can take control of your data at its furthest outposts and bring it to the data center in a cost-effective
way. Using replication, you can protect data anywhere.
HP StorageWorks VLS and D2D Solutions Guide 23
Figure 5 Enterprise Deployment with Small and Large Remote and Branch Offices
.
Replication provides end-to-end management of backup data from the small remote office to the
regional site and finally into the primary data center, all controlled from the primary data center,
while providing local access to backup data as well. Note that replication is within device families
(VLS to VLS, D2D to D2D).
HP StorageWorks Replication Solutions
Most companies now recognize the importance of a robust backup and restore data protection
strategy, although only enterprise level users tend to invest in site disaster recovery. In most cases,
data protection is in the form of daily off-siting of physical tapes. However, even the offsiting of
physical tapes has its down sides—a high level of manual intervention, tape tracking requirements,
etc. The physical transfer of tapes off-site is not very automated.
In addition, one of the pain points for many companies large and small is protecting data in remote
offices. Untrained IT staff manage a daily backup process involving changing of physical tapes, and
the process is prone to human error.
HP replication, available on its VLS and D2D systems, now offers the solution to both these problems.
You can replicate local backup data (virtual cartridges) between sites in a reliable, automated manner
at a fraction of the costs previously required when using high bandwidth links or in some cases physical
tape offsiting.
Consider the “Before” and “After” scenarios detailed below.
Concepts24
Figure 6 Remote Site Data Protection Before Replication
.
Figure 7 Remote Site Data Protection Using Replication
.
Deduplication is the key technology enabler for replication on HP VLS and D2D systems. (VLS systems
use HP Accelerated deduplication, and D2D systems use Dynamic deduplication.) The same technology
HP StorageWorks VLS and D2D Solutions Guide 25
that allows duplicate data to be detected and stored only once on the HP VLS or D2D system also
allows only the unique data to replicate between sites. Because the volume of data being replicated
between sites is much less than if the full data set was replicated, you can use lower bandwidth links
at correspondingly lower price points. In addition, backup at remote offices can be automated to a
local virtual tape library and then replicated back to a regional data center or primary data center
allowing end-to-end management from the data center of all data in the remote offices.
This transformation is shown in Table 5 which compares the amount of data to transfer both with and
without deduplication. The amount of data to back up in this example is 1 TB.
Table 5 Estimated Time to Replicate Data for a 1 TB Backup Environment at 2:1
Link Type
OC12T3T1Data Sent
622.1 Mb/s44.7 Mb/s1.5 Mb/sLink Rate (66% efficient)
Without deduplicationBackup Type
16 minutes3.8 hours4.5 days50 GBIncremental
2.7 hours1.6 days45.4 days500 GBFull
With deduplicationChange Rate
4.3 minutes59 minutes29 hours13.1 GB0.5%
NOTE:
T1/T3 and OC12 are old terms with respect to WAN link terminology. Many link providers use their
own names (e.g., IP Clear, Etherflow). This document distinguishes them by their speed using 2
Mbits/sec, 50 Mbits/sec, etc.
One consideration with replication is that you must “initialize” the Virtual Tape Libraries with data
prior to starting the replication. This ensures that the source and target devices are both synchronized
with the relevant reference data to allow them to interpret the changed data (deltas) that comes across
the WAN link during replication.
Replication Deployment Options
You can deploy the HP VLS and D2D systems for replication in many ways depending on your
requirements. You should understand the terminology associated with deduplication and replication.
The key terminology for replication deployment:
• Source: A series of slots/cartridges in a virtual library that act as the source data to replicate. This
is the original copy of the backup data, written to and managed by the source site’s backup application.
• Target or LAN/WAN destination: A series of corresponding slots in another virtual library on
another site in another location which receives data from the source library. This is the secondary
(disaster recovery) copy of the backup data, managed by the replication system.
5.3 minutes73 minutes35 hours16.3 GB1.0%
7.3 minutes102 minutes49 hours22.5 GB2.0%
Concepts26
For both HP VLS and D2D systems, the unit of replication is a virtual cartridge and the replication link
is TCP/IP (one GbE connection per node on the VLS system, and one to two GbE connections on the
D2D system). Figure 8 shows how you can configure the system to replicate all of the cartridges or
just a subset of cartridges from the source virtual library to the target virtual library.
Figure 8 Replication Configuration Options
.
• Active-Passive: The best deployment for a single site disaster recovery protection. The active source
device receives the local backup data and then replicates it to a passive target device at the disaster
recovery site dedicated to receiving replication data.
• Many-to-one: The best deployment for several smaller sites consolidating their replication to a
central disaster recovery site. Each source device in the smaller sites replicate to a central target
device which you configure to have multiple sources replicate to a common virtual library on the
central device (each source replicates to its own subset of the cartridges in the virtual library). Alternatively, each source can have its own dedicated virtual library. Up to four remote VLS sites
can copy to a single HP VLS at the central site at launch, and this will be increased over time. Up
to 16 remote D2D sites can copy to a single D2D4000 at the central site, and up to 24 remote
D2D sites can copy to a D2D4100.
• Active-Active and N-Way: The best deployment for sharing your VLS or D2D system hardware for
both receiving backups and receiving replication data (so each device is both a source and a
target as shown in the above diagram). Active-active is one way to implement cross-replication
between sites, but you can use two active-passive deployments to achieve the same result.
Choosing between either active-active or 2x active-passive deployments for cross-replication depends
on which provides the lowest cost. Active-active is only recommended if the backup traffic on each
device is only using up to half of the device’s maximum performance and capacity, because you
need additional performance and capacity for the replication target operations.
For example, if you have two VLS9000 sites that each requires 2-nodes/2-arrays for just their
backup performance/capacity and 2-nodes/2-arrays for their replication target performance/capacity, then you have the following choices for cross-replication deployment:
HP StorageWorks VLS and D2D Solutions Guide 27
• Active-Active: Each site requires a 4-node/4-array VLS9000 (with deduplication) shared
between backups and replication target, one rack, and four replication LTUs.
• 2x Active-Passive: Each site requires a 2-node/2-array VLS9000 (with deduplication) for backup
and a separate 2-node/2-array VLS9000 (with deduplication) for replication target, two racks,
and two replication LTUs.
In this example, it costs less to use active-active because it adds two replication LTUs but saves the
hardware/power/footprint cost of a second rack and the cost of a second VLS connectivity kit.
However, if your backups required more than half of the maximum device performance (for example, more than two nodes out of a maximum configuration of four nodes), you may have to
deploy two devices per site. In this case, it would be cheaper licensing (and better future device
scalability) to use 2x active-passive deployment.
NOTE:
Multi-hop replication (replicating a cartridge from device A to device B, and then replicating the
replicated cartridge from device B to device C) is not yet supported.
Backup Application Interaction with Replication
The replication in both the VLS and D2D systems is mirroring the source cartridge to its matching
target cartridge so both cartridges have the same barcode, the same tape contents, etc. Backup
applications currently cannot handle seeing two copies of the same cartridge at the same time (because
to the backup application, the cartridge is a single entity in the media database). Given this limitation,
you must hide the target virtual library from the source device’s backup application:
• For VLS systems, the replication target is a subset or an entire virtual library that is presented on
front-end Fibre Channel ports, so if the source backup application is running media agents on the
target site you either need to use SAN zoning or the device’s LUN mapping feature to hide this
replication target virtual library from the source device’s backup application.
• For D2D systems, this is currently automatic because the replication target is hidden from all ex-
ternal host access (until it is converted into a non-replicating library in the event of a disaster recovery).
Figure 9 Presenting the Replication Target to a Different Backup Application
.
Concepts28
On a VLS (by default) or a D2D (if you enable the read-only mode on the target library), you can still
present the replication target to a different backup application instance (i.e., a separate backup
application master/cell server on the target site with its own media database), which you can use to
“import” replicated cartridges into its media database and then perform restores or copy to physical
tape, etc. See “Creating Archive Tapes from the Target” on page 190 (VLS) or
“Creating Archive Tapes from the Target” on page 99 (D2D) for an example on automating this.
NOTE:
With HP Data Protector, if you have a cell server in each site that can share library devices across
sites through a MoM/CMMDB, you still need to ensure that each cell server only sees its local virtual
library (i.e., the source cell server must not be configured to see the target virtual library and vice-versa).
Replication Limitations
VLS and D2D replication may not work in every environment. Understand the possible limitations:
• Do not confuse Virtual Tape Library replication with “high availability/continuous access” which
is a type of full bandwidth replication used on Disk Array technology whereby primary application
data can be accessed within hours of a disaster at one site from the other site. Virtual tape replication is not high availability; it is a means of automating the offsiting of data resulting in better
disaster recovery coverage.
• System data rate change. The higher the data change rate, the more data requires replicating.
Systems with very high change rates and slower links may not be able to replicate all the data
off-site within 24 hours.
• High latency links. For very large distance replications with many routers involved, the latency of
the WAN link may lead to high inefficiency of the link where throughput is limited and replications
cannot be performed in a timely manner.
• Current link speed is too slow or the implementation of replication on the existing link will cause
unacceptable delays in application response times. Using the HP StorageWorks sizer tool and
some of your inputs, you can evaluate if you will need to increase an existing link speed to be
able to benefit from replication. See http://www.hp.com/go/storageworks/sizer.
• Some additional financial investment will be required as increased bandwidth links, hardware
additions, and/or deduplication and replication licenses, but in general the increased robustness
of the data protection process should pay for itself within 2–3 years.
• On the VLS, the HP Accelerated deduplication relies on understanding the metadata format of the
incoming data stream. It does not currently support all data formats and backup API’s. In the case
where an HP VLS cannot deduplicate the data type, the data is sent untouched to the VLS. This
data is replicated as “whole cartridge;” the entire tape contents are replicated and not the delta’s
or unique data objects. If a high percentage of your date cannot deduplicate, the volume of data
to replicate will be very large. If you do not have very large volumes of data to replicate, you
should consider using HP whole cartridge replication. This works essentially in the same way as
replication using echo copy pools; it requires no tape transfer or initialization and no deduplication
or replication licenses. However, all data is transferred between sites and this means the WAN
links will have to considerably higher performance at an associated higher cost.
HP StorageWorks VLS and D2D Solutions Guide 29
Concepts30
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