HP Storage Mirroring Software User Manual
Storage Mirroring for Linux
User’s Guide
Third Edition (April 2009)
Part Number: T2558-96317
© Copyright 2009 Hewlett-Packard Development Company, L.P.
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HP StorageWorks Storage Mirroring for Linux User’s Guide
Third Edition (April 2009)
Part Number: T2558-96317
Double-Take, Balance, Double-Take Cargo, Double-Take Flex, Double-Take for Hyper-V, Double-Take for Linux, Double-Take
Move, Double-Take ShadowCaster, Double-Take for Virtual Systems, GeoCluster, Livewire, netBoot/i, NSI, sanFly, TimeData,
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its affiliates and subsidiaries in the United States and/or other countries. Microsoft, Hyper-V, Windows, and the Windows logo
are trademarks or registered trademarks of Microsoft Corporation in the United States and/or other countries. Linux is a
registered trademark of Linus Torvalds. Red Hat is a registered trademark of Red Hat, Inc. in the United States and other
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countries. All other trademarks are the property of their respective companies.
© 1996-2009 Double-Take Software, Inc. All rights reserved.
Table of Contents
Chapter 1 Introduction .........................................................1-1
Storage Mirroring operations ............................................................ 1-3
Mirroring ............................................................................................................. 1-3
Replication ........................................................................................................... 1-4
Failure monitoring and failover ............................................................................... 1-5
Restoration .......................................................................................................... 1-6
Sample configurations ...................................................................... 1-7
One-to-one, active/standby .................................................................................... 1-7
One-to-one, active/active ...................................................................................... 1-8
Many-to-one ........................................................................................................ 1-9
One-to-many ..................................................................................................... 1-10
Chained ............................................................................................................. 1-11
Single server ...................................................................................................... 1-12
Virtual systems .................................................................................................. 1-13
Resources ....................................................................................... 1-14
Chapter 2 Installation ...........................................................2-1
System requirements ........................................................................ 2-1
Installing or upgrading Storage Mirroring for Linux .......................... 2-3
Configuring your servers using DTSetup ........................................... 2-4
Installing or Upgrading the Storage Mirroring Client for Windows .... 2-9
Removing (Erasing) Storage Mirroring ........................................... 2-10
Removing the Storage Mirroring Client for Windows ...................... 2-10
Chapter 3 Clients ..................................................................3-1
Management Console ........................................................................ 3-1
Logging on and off of Storage Mirroring ................................................................... 3-2
Storage Mirroring workspaces ................................................................................. 3-3
Saving a workspace ......................................................................................... 3-3
Opening a workspace ....................................................................................... 3-3
Failover Control Center ..................................................................... 3-4
Configuring communication ports ............................................................................ 3-4
Configuring refresh rate ......................................................................................... 3-4
Clearing maintained security credentials .................................................................. 3-4
Chapter 4 Replication Sets ....................................................4-1
Replication capabilities ..................................................................... 4-3
Creating a replication set .................................................................. 4-5
Creating or modifying replication rules manually .............................. 4-6
Selecting a block device for replication.............................................. 4-7
Modifying a replication set ................................................................ 4-7
Renaming and copying a replication set ........................................... 4-7
Deleting a replication set .................................................................. 4-7
Calculating replication set size ......................................................... 4-8
i
Chapter 5 Establishing a Connection Using the Connection
Wizard ..................................................................................5-1
Chapter 6 Establishing a Connection Using the Connection
Manager ...............................................................................6-1
Chapter 7 Establishing a Connection Across a NAT or
Firewall ................................................................................7-1
Verifying the Storage Mirroring port settings ................................... 7-1
Configuring the hardware ................................................................. 7-2
Inserting the servers in the Management Console ............................ 7-2
Establishing the connection .............................................................. 7-2
Chapter 8 Simulating a Connection .......................................8-1
Gathering system information .......................................................... 8-1
Establishing the simulated connection .............................................. 8-2
Chapter 9 Managing Connections ..........................................9-1
Monitoring connections .................................................................... 9-2
Monitoring the message window ...................................................... 9-6
Queuing Storage Mirroring data ........................................................ 9-8
Understanding queuing .......................................................................................... 9-8
Configuring queuing ............................................................................................ 9-10
Configuring automatic reconnections ............................................. 9-12
Configuring compression ...................................................................................... 9-13
Disconnecting a connection ............................................................ 9-13
Chapter 10 Mirroring and Replication .................................10-1
Controlling mirroring ................................ ...................................... 10-1
Controlling an automatic mirror ...................................................... 10-3
Configuring and removing orphan files ........................................... 10-5
Starting replication ......................................................................... 10-6
Chapter 11 Verification .......................................................11-1
Manual verification ......................................................................... 11-1
Scheduled verification .................................................................... 11-2
Verification log ............................................................................... 11-3
Chapter 12 Data Transmission ............................................12-1
Controlling transmission manually ................................................ . 12-1
Controlling a target manually ........................................................ . 12-1
Scheduling transmission criteria and bandwidth limiting ................ 12-2
ii
Chapter 13 Failover and Failback ........................................13-1
Configuring failover ........................................................................ 13-1
Editing failover configuration ......................................................... 13-3
Removing failover configuration ..................................................... 13-4
Monitoring failover ......................................................................... 13-4
Testing failover ............................................................................... 13-5
Failover manual intervention .......................................................... 13-5
Initiating failback ........................................................................... 13-6
Chapter 14 Restoration .......................................................14-1
Chapter 15 Monitoring Tools ...............................................15-1
Log files .......................................................................................... 15-2
Viewing the log files ............................................................................................ 15-3
Log messages .................................................................................................... 15-4
Linux System Log ........................................................................... 15-9
DTStat .......................................................................................... 15-19
Configuring the statistics file ...............................................................................15-20
Running DTStat from the command prompt ...........................................................15-21
DTStat statistics ................................................................................................15-22
SNMP ............................................................................................ 15-26
Configuring SNMP ..............................................................................................15-26
SNMP statistics ..................................................................................................15-27
SNMP traps .......................................................................................................15-29
Chapter 16 Server Settings .................................................16-1
General ........................................................................................... 16-2
Setup .............................................................................................. 16-4
Network .......................................................................................... 16-5
Queue ............................................................................................. 16-6
Source ............................................................................................ 16-8
Target ........................................................................................... 16-10
Database ...................................................................................... 16-11
Logging ......................................................................................... 16-12
E-mail notification ........................................................................ 16-13
Chapter 17 Security ............................................................17-1
Security access levels ..................................................................... 17-1
Security advantages and considerations ......................................... 17-1
Clearing maintained security credentials ........................................ 17-2
Index........................................................................................ I
iii
Introduction
Welcome to Storage Mirroring® for Linux®! Storage Mirroring is a
real-time data replication and failover software product. Storage
Mirroring augments your existing data protection strategy by
reducing downtime and data loss, and it provides these services with
minimal impact on existing network and communication resources.
Storage Mirroring allows you to specify mission-critical data that must be protected and replicates,
in real-time, that data from a production server, known as the source, to a backup server, known as
the target. The target server, on a local network or at a remote site, stores the copy of the critical
data from the source. Storage Mirroring monitors any changes to the critical data and sends the
changes to the target server. By replicating only the file changes rather than copying an entire file,
Storage Mirroring allows you to more efficiently use resources.
Offsite disaster recovery services—No business is immune from the many disasters - disk
crashes, power failures, human error, natural disasters - that will inevitably stop the flow of data
at one or more of your facilities. Tape-based disaster recovery can only restore data to the point
of the last backup, which was most likely the prior night. Any data created since the last backup
will be lost. An effective disaster recovery plan requires a comprehensive data protection plan,
including Storage Mirroring continuous data replication.
Storage Mirroring can be combined with your existing tape backup solution for a more
comprehensive disaster recovery plan. Storage Mirroring is a disaster recovery software based
on asynchronous real-time replication and automatic failover to provide cost-effective business
continuity for Microsoft
servers, and many other applications. Storage Mirroring provides continuous data protection by
sending an up-to-the-minute copy of the data as it is being changed to the target server.
Features such as built-in bandwidth control allows data to be replicated to a remote source, far
from harms way of a disaster such as hurricanes, tornadoes, and brown-outs. That same
bandwidth control allows data to be restored within minutes.
Local high availability services—As businesses come to increasingly depend on continuous
access to their data, ensuring that their data is available on-demand is of paramount importance.
Traditional solutions, such as tape backup and hardware mirroring, are not without flaws. Tape
backup poses a potential risk in that data backups must be performed when the system is idle,
meaning that as much as a day's worth of data could be lost. Tape recovery time can also be below
many business's recovery time objectives (and does not provide high availability).
A more cost-effective answer to a high availability solution is asynchronous host-based
replication for high availability. Support for non-proprietary hardware and storage systems
means you can leverage your existing resources. You will also get real-time data protection
without distance limitations, ensuring high availability for all your business-critical applications,
including e-mail. Real-time data replication at the byte level, regardless of application, is a much
more efficient use of computing and bandwidth resources for high availability. With Storage
Mirroring all of your applications can have cost-effective, real-time data protection and high
availability.
Enhanced centralized backup—The rapid growth in storage brought on by the Internet and
distributed computing has placed nearly impossible demands on administrators responsible for
protecting corporate data assets. The backup window has shrunk to nearly zero and tape backup
systems can introduce significant overhead to a production server, seriously impacting its
performance. While the importance of backups increases, the impact of periodic full system
backups is obvious. Even nightly incremental backups dominate processing while they examine
every file system object and then read all files that have changed in their entirety for backup.
Performing this process across a network adds additional overhead as the entire process happens
across the wire.
These days permanent point in time storage and recovery, like that provided by periodic tape
backup, is required. And despite the fact that Storage Mirroring cannot provide a way to retrieve
historical file versions or files that may have been previously deleted by users, Storage Mirroring
can enhance the backup process by continuously replicating critical data to centralized servers
and using tape backup systems to backup the replica rather than the production servers. Using
Storage Mirroring offloads the burden of periodic tape backups from multiple production servers
to a dedicated backup server and makes centralized tape backup a reality, significantly reducing
management cost and improving reliability. Regardless of a file’s state on the source, on the
target every file is closed and available for consistent backup at any point in time.
®
Exchange, Microsoft SQL Server®, Oracle®, virtual systems, file
1
1 - 1
The following diagram is one common Storage Mirroring configuration.
Testing or Migration
Offsite Disaster
High Availability
Centralized
Production (Source) Servers
(Target) Server
Tape Backup
Server
Recovery Server
1 - 2
Storage Mirroring operations
Source Target
2/4
1/29
All files can be
Checksums can
calculate blocks to
Different files can
be mirrored
New files are mirrored
Identical files are
not mirrored
Flexible mirroring options allow you to choose
which files are mirrored from the source to the target.
mirrored
be mirrored
Storage Mirroring performs four basic types of operations.
Mirroring—The initial copy or subsequent resynchronization of selected data
Replication—The on-going capture of byte-level file changes
Failure monitoring and failover—The ability to monitor and stand-in for a server, in the event
of a failure
Restoration—A mirror of selected data from the target back to the source
Mirroring
Mirroring is the process of transmitting user-specified data from the source to the target so that an
identical copy of data exists on the target. When Storage Mirroring initially performs mirroring, it
copies all of the selected data, including file attributes and permissions. Mirroring creates a
foundation upon which Storage Mirroring can efficiently update the target server by replicating only
file changes.
If subsequent mirroring operations are necessary, Storage Mirroring can mirror specific files or blocks
of changed data within files. By mirroring only files that have changed, network administrators can
expedite the mirroring of data on the source and target servers.
Mirroring has a defined end point - when all of the selected files from the source have been
transmitted to the target. When a mirror is complete, the target contains a copy of the source files
at that point in time.
1 - 3
Replication
Source Target
User or application updates
part of a file
Only the changed
portion of the file is
Up-to-date copy maintained
on the target
replicated
Replication is the real-time transmission of file changes. Unlike other related technologies, which are
based on a disk driver or a specific application, the Storage Mirroring replication process operates at
the file system level and is able to track file changes independently from the file’s related application.
In terms of network resources and time, replicating changes is a more efficient method of maintaining
a real-time copy of data than copying an entire file that has changed.
After a source and target have been connected through Storage Mirroring, file system changes from
the user-defined data set are tracked. Storage Mirroring immediately transmits these file changes to
the target server. This real-time replication keeps the data on the target up-to-date with the source
and provides high availability and disaster recovery with minimal data loss.
Unlike mirroring which is complete when all of the files have been transmitted to the target,
replication continuously captures the changes as they are written to the source. Replication keeps the
target up-to-date and synchronized with the source.
1 - 4
Failure monitoring and failover
Source Target
User and application requests
sent to the source name or IP address
Mirroring and replicating data
Failure monitoring
Before failover occurs
Source Target
User and application requests
sent to the source name or IP address
After failover occurs
which is now running o the target
X
Failover is the process in which a target stands in for a failed source. As a result, user and application
requests that are directed to the failed source are routed to the target.
Storage Mirroring monitors the source status by tracking network requests and responses exchanged
between the source and target. When a monitored source misses a user-defined number of requests,
Storage Mirroring assumes that the server has failed. Storage Mirroring then prompts the network
administrator to initiate failover, or, if configured, it occurs automatically.
The failover target assumes the network identity of the failed source. When the target assumes the
identity of the source, user and application requests destined for the source server or its IP
address(es) are routed to the target.
When partnered with the Storage Mirroring data replication capabilities, failover routes user and
application requests with minimal disruption and little or no data loss. In some cases, failover may
be used without data replication to ensure high availability on a server that only provides processing
services, such as a web server.
1 - 5
Restoration
Source Target
2/4
2/5
All files can be
Checksums can
calculate blocks to
Different files can
be restored
New files are restored
Identical files are
not restored
Flexible restoration options allow you to choose
which files are restored from the target to the source.
restored
be restored
Restoration provides an easy method for copying replicated data from the target back to its original
location on the source. The process only requires you to select the source, target, and the
appropriate replication set. There is no need to select files or to remember where the data came from
on the source since that information is maintained by Storage Mirroring.
Restoration can be used if the source data is lost due to a disk crash or when the most up-to-date
data exists on the target due to failover. At the time of a source server failure, your Storage Mirroring
target will contain the same data as your Storage Mirroring source. If you are using the Storage
Mirroring failover capabilities, users can continue updating data on the target server while the
problems on the source are resolved. Because of the continued updates on the target, when the
source server is ready to come back online, the two servers will no longer contain the same data.
Restoration is the process of copying the up-to-date data from the target back to the original source
or a new source.
When a restoration is complete, the source and target are again synchronized.
1 - 6
Sample configurations
Source
(Active)
Target
(Standby)
Storage Mirroring is an exceptionally flexible product that can be used in a wide variety of network
configurations. To implement Storage Mirroring effectively, it is important to understand the possible
configuration options and their relative benefits. Storage Mirroring configuration options can be used
independently or in varying combinations.
NOTE: The Storage Mirroring replication and failover features have different server
requirements. If you use Storage Mirroring to monitor and stand in for failed servers, the
source and target must have identical versions of operating system and applications. By
contrast, Storage Mirroring replication operations do not require that the source and
target servers have identical versions of operating system and applications.
One-to-one, active/standby
Description One target server, having no production activity, is dedicated to support one
source server. The source is the only server actively replicating data.
Applications This configuration is appropriate for offsite disaster recovery, failover, and
critical data backup. This is especially appropriate for critical application
servers such as Exchange, SQL Server, and web servers.
This is the easiest configuration to implement, support, and maintain.
Considerations This configuration requires the highest hardware cost because a target server
is required for every source server.
1 - 7
One-to-one, active/active
Data from first source
Data from second source
Source and Target
(Active)
Target and Source
(Active)
Description Each server acts as both a source and target actively replicating data to each
other.
Applications This configuration is appropriate for failover and critical data backup. This
Considerations Coordination of the configuration of Storage Mirroring and other applications
configuration is more cost-effective than the Active/Standby configuration
because there is no need to buy a dedicated target server for each source.
In this case, both servers can do full-time production work.
can be more complex than the one-to-one active/standby configuration.
During replication, each server must continue to process its normal workload.
Administrators must avoid selecting a target destination path that is included
in the source’s replication set. Any overlap will cause an infinite loop.
To support the production activities of both servers during failover without
reducing performance, each server should have sufficient disk space and
processing resources.
Failover and failback scripts must be implemented to avoid conflict with the
existing production applications.
1 - 8
Many-to-one
Source
TargetSource
Source
Description Many source servers are protected by one target server.
Application This configuration is appropriate for offsite disaster recovery. This is also an
Considerations The target server must be carefully managed. It must have enough disk
excellent choice for providing centralized tape backup because it spreads the
cost of one target server among many source servers.
space and RAM to support replication from all of the source systems. The
target must be able to accommodate traffic from all of the servers
simultaneously. If using failover, scripts must be coordinated to ensure that,
in the event that the target server stands in for a failed server, applications
will not conflict.
1 - 9
One-to-many
Target
Source Target
Target
Description One source server sends data to multiple target servers. The target servers
Applications This configuration provides offsite disaster recovery, redundant backups, and
Considerations Updates are transmitted multiple times across the network. If one of the
may or may not be accessible by one another.
data distribution. For example, this configuration can replicate all data to a
local target server and separately replicate a subset of the mission-critical
data to an offsite disaster recovery server.
target servers is on a WAN, the source server is burdened with WAN
communications.
1 - 10
Chained
Source Target and Source Target
Description The source servers sends replicated data to a target server, which acts as a
Applications This is a convenient approach for integrating local high availability with offsite
Considerations The target/source server could become a single point of failure for offsite data
source server and sends data to a final target server, which is often offsite.
disaster recovery. This configuration moves the processing burden of WAN
communications from the source server to the target/source server.
After failover in a one-to-one, many-to-one, or one-to-many configuration,
the data on the target is no longer protected. This configuration allows
failover from the first source to the middle machine, with the third machine
still protecting the data.
protection.
1 - 11
Single server
Source and Target
Replication set data
Copy of replication set data
C:\Data
D:\Data
on specified target path
Description Source and target Storage Mirroring components are loaded on the same
Applications This configuration is useful for relocating data within existing servers so that
Considerations This configuration does not provide high availability for the entire server. This
server allowing data to be replicated from one location to another on the
same volume or to a separate volume on the same server. These could be
locally attached SCSI drives or Fibre Channel based SAN devices.
open files can be backed up. If the source and target copies of the data are
located on different drives, this configuration does support high availability
of the replication set in the event that the source hard drive fails.
configuration must be configured carefully so that an infinite loop is not
created.
1 - 12
Virtual systems
Source Target
Virtual to virtual configuration
Source
Physical to vir tual configuration
Guest
Guest
Guest
Guest
Host
Guest
Guest
Guest
Guest
Host
Target
Guest
Guest
Guest
Guest
Host
Source
Source
Source
Description Source and/or target Storage Mirroring components are loaded on the guest
Applications This configuration easily protects virtual environments. When combined with
Considerations This configuration does not protect data outside of the virtual system.
operating system allowing data to be replicated between virtual systems.
One Storage Mirroring for Virtual Machines license can be used on up to five
virtual servers.
physical servers, this configuration offers additional flexbility.
1 - 13
Resources
You have many resources available to you when using Storage Mirroring.
Operating System and application documenta ti on—Make sure that you have complete
documentation for your operating system and your applications.
Storage Mirroring documentation—The complete set of Storage Mirroring documentation
inc ludes the man u a ls listed b elow. Each manu al is available in the \DblTake\docs directory on the
product CD and in the root of the installation directory you selected during the installation. The
manuals are in Adobe
Reader
Storage Mirroring fo r Linux User’s Guide—This guide is a complete how-to guide with detailed
®
by downloading the latest version from the Adobe web site at www.adobe.com.
steps for installing and using Storage Mirroring. This guide also contains a complete list of
Storage Mirroring messages, alerts, and statistics. The file name of this manual is User’s
Guide.pdf.
Storage Mirroring fo r Linux Scripting Guide—This guide is a scripting manual for those users
who want to use DTCL (Double-Take Command Language). The file name of this manual is
Scripting Guide.pdf.
Storage Mirroring for Lin ux Evaluation Guide—This guide is for those users who are evaluating
Storage Mirroring. It walks through specific steps allowing you to become familiar with the
Storage Mirroring core technology first hand. The file name of this manual is Evaluation
Guide.pdf.
Storage Mirroring Online Help—The Storage Mirroring Management Console and Failover
Control Center contain context-sensitive online help. The online help can be accessed by pressing
the F1 key, clicking the Help button on screens where it is available, or selecting Help, Help
Topics.
Readme—Storage Mirroring includes a readme file which contains any last-minute information.
This file is called readme.html and is located in the \DblTake\docs directory of the product CD and
in the root of the installation directory you selected during the installation.
®
Acrobat® PDF format. If needed, you can install the free Adobe Acrobat
1 - 14
Installation
Review System requirements on page 2-1 and then use the
appropriate instructions from the following list to meet your goal.
Installing or upgrading Storage Mirroring for Linux on
page 2-3—Use these instructions if you are installing or upgrading on a Linux server.
Configuring your servers using DTSetup on page 2-4—Use these instructions to configure
your Storage Mirroring servers.
Installing or Upgrading the Storage Mirroring Client for Windows on page 2-9—Use these
instructions if you want to install or upgrade Storage Mirroring on a Windows® client.
Removing (Erasing) Storage Mirroring on page 2-10—Use these instructions if you want to
remove Storage Mirroring from a Linux server.
Removing the Storage Mirroring Client for Windows on page 2-10—Use these instructions
if you want to uninstall Storage Mirroring from a Windows client.
System requirements
Verify that each machine that will be used as a Storage Mirroring source or target meets the following
system requirements.
Operating System—Make sure your servers meets the operating system requirements outlined
in the following table.
Physical Servers and
Virtual Machines Guest
Operating Systems
Red Hat
®
Enterprise
Linux 4.5 through 4.7
for 32-bit architecture
CentOS 4 Updates 5-7
for 32-bit architecture
Red Hat Enterprise
Linux 4.5 through 4.7
for 64-bit architecture
CentOS 4 Updates 5-7
for 64-bit architecture
Red Hat Enterprise
Linux 5.0 through 5.3
for 32-bit architecture
CentOS 5 GA-Update 2
for 32-bit architecture
Red Hat Enterprise
Linux 5.0 through 5.3
for 64-bit architecture
CentOS 5 GA-Update 2
for 64-bit architecture
Kernel
Version
2.6.9.x.x
2.6.18.x.x
Kernel Type
Default
SMP
HugeMem
Default
SMP
LargeSMP
Default (SMP)
Xen
PAE
Default (SMP)
Xen
File
System
Ext2
Ext3
Virtual Machines
Platforms
VMware
Microsoft
®
Virtual Server
Xen
Virtual Iron
®
®
2 - 1
Physical Servers and
Virtual Machines Guest
Operating Systems
SUSE Linux Enterprise
Server 10.2 for 32-bit
architecture
Kernel
Version
2.6.16.x.x
Kernel Type
Default
SMP
BigSMP
Xen
XenPAE
File
System
Ext2
Ext3
ReiserFS
Virtual Machines
Platforms
VMware
Microsoft
®
Virtual Server
Xen
Virtual Iron
®
®
SUSE Linux Enterprise
Server 10.2 for 64-bit
architecture
Default
SMP
Xen
NOTE: Because Storage Mirroring has operating system dependent files, if you are upgrading
your operating system (to a new major version, not a service pack) and have Storage
Mirroring installed, you must remove Storage Mirroring prior to the operating system
upgrade. Uninstall Storage Mirroring, perform the operating system upgrade, and
then reinstall Storage Mirroring.
System Memory—At a minimum, you should have 512 MB of memory on each server. Ideally,
you should have 1 GB.
Disk Usage—The amount of disk space required for the Storage Mirroring program files is
approximately 45 MB. About 5 MB will be located on your
/(root) partition, and the remainder
will be on your /usr partition. You will need to verify that you have additional disk space for
Storage Mirroring queuing, logging, and so on. Additionally, on a target server, you need sufficient
disk space to store the replicated data from all connected sources, allowing additional space for
growth.
Protocols—TCP/IP
Name resolution—Your servers must have name resolution using hosts files entries, DNS,
and/or DHCP. For details on configuring name resolution by any of these methods, see your Linux
documentation or online Linux resources.
2 - 2
Installing or upgrading Storage Mirroring for Linux
Use these instructions if you are installing or upgrading Storage Mirroring.
1. Determine the installation package that is appropriate for your operating system.
Operating System Installation File
32-Bit Operating System StorageMirroring-versionnumbers.i386.rpm
64-Bit Operating System StorageMirroring-versionnumbers.x86_64.rpm
The versionnumbers in the installation file name will vary and will correspond to the version of
Storage Mirroring you are installing. For example, if you are installing version 4.5.11.0.2200, the
installation files would be StorageMirroring-4.5.11.0-2200.i386.rpm or
StorageMirroring-4.5.11.0-2200.x86_64.rpm. If you are uncertain about the architecture of
your machine, you can use the uname -m command to determine it.
2. Once you have determined the appropriate installation package to use, you can install the
software from the UI or from the command line.
UI installation—Double-click the .rpm file from the UI and confirm the installation or
upgrade.
Command line installation—Use the following steps to install from a command line.
a. Go to a shell prompt by launching a terminal application from your UI or logging in via the
Linux virtual console.
b. If you are not already, become the superuser ("root") by typing su -.
c. If you are installing from a CD, mount the file ISO 9660 or UDF file system.
d. To run the installation use rpm -i with the installation file name to install the software or
rpm -U with the installation file name to upgrade the software. For example, if you were
installing on a 32-bit operating system, you would use the command rpm -i
StorageMirroring-4.5.11.0-2200.i386.rpm.
A successful installation returns you to the shell prompt. If you receive an error message
during the installation, you will need to reinstall the software. If you are unable to resolve the
error, contact technical support.
3. After you have installed the software, you need to configure your installation prior to using
Storage Mirroring. Run the following command from the shell prompt.
DTSetup
NOTE: Do not run DTSetup using the sudo command. Use a real root shell to launch DTSetup
instead, either by logging in as root on the console or by using the login session of a
non-privileged user to run su - to start a root shell.
4. The first time you run DTSetup after an installation or upgrade, you will be prompted to review
the HP license agreement. Review the agreement and accept the terms of agreement by typing
yes. You cannot use Storage Mirroring without agreeing to the licensing terms.
5. When the DTSetup menu appears, at a minimum you must specify an activation code, configure
replication, and start the daemon. You may also desire to modify the security group
configuration. During the install, root is automatically added to the main Storage Mirroring
security group. If you want to add other users or remove root, you should modify the security
group configuration as well. For details on all of the DTSetup menu options, see Configuring
your servers using DTSetup on page 2-4.
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Configuring your servers using DTSetup
DTSetup is a menu-driven application to provide easy access to Storage Mirroring server
configuration.
1. Run the following command from the shell prompt to start DTSetup.
DTSetup
NOTE: Do not run DTSetup using the sudo command. Use a real root shell to launch DTSetup
instead, either by logging in as root on the console or by using the login session of a
non-privileged user to run su - to start a root shell.
2. The first time you run DTSetup after an installation or upgrade, you will be prompted to review
the HP license agreement. Review the agreement and accept the terms of agreement by typing
yes. You cannot use Storage Mirroring without agreeing to the licensing terms.
3. When the DTSetup menu appears, enter the number of the menu option you want to access. Use
the following list (with corresponding menu numbers) to understand each menu option.
=== DTSetup Main Menu ===
Menu Options:
1. Setup tasks
2. Start/Stop Storage Mirroring daemon
3. Start User Interface (DTCL -i)
4. Documentation/Troubleshooting tasks
Q. Quit DTSetup
Please choose a menu option :
1. Setup tasks—Several setup tasks are required for Storage Mirroring functionality, including
an activation code for each server, at least one user in the Storage Mirroring administrator
group, and replication configuration for your source. The remaining items in the setup menu
are also Storage Mirroring configuration related, but are optional.
1.1. Set activation code—For each server, you must specify a unique activation code,
which is an alpha-numeric code that applies the appropriate Storage Mirroring license
to your installation.
1.2. Add/Remove users to Storage Mirroring groups—Storage Mirroring uses the
native operating system to provide security. Privileges are granted through
membership in user groups defined on each machine running Storage Mirroring. To
gain access to a particular Storage Mirroring source or target, the user must provide a
valid operating system user name and password and the specified user name must be a
member of one of the Storage Mirroring security groups. The administrator group
(dtadmin) provides full privileges and the monitor group (dtmon) provides a subset of
privileges. During the install, root is automatically added to the Storage Mirroring
administrator group. See Security on page 17-1 for details on security and the specific
privileges granted to each group.
1.2.1. Add Storage Mirroring Administrator—This option adds users to the Storage
Mirroring administrator group.
1.2.2. Remove Storage Mirroring Administrator—This option removes users from
the Storage Mirroring administrator group
1.2.3. Add Storage Mirroring Monitor—This option adds users to the Storage
Mirroring monitor group.
1.2.4. Remove Storage Mirroring Monitor—This option removes users from the
Storage Mirroring monitor group.
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1.3. Configure File System or Block Device Replication—Storage Mirroring hooks
operations for replication by interjecting itself between the kernel VFS layer and the
underlying file system. This must be done on a case by case basis for each block
device, mount point, or parent directory that needs to be replicated.
NOTE: When making changes replication configuration changes, stop any
applications that may be running and restart them after the replication
changes have been made. Storage Mirroring needs to be loaded on the file
system before any applications, otherwise some data may not be replicated.
1.3.1. Configure File System Replication setup file—In order to use Storage
Mirroring replication, data that will be replicated must reside on a partition,
which is specially mounted with the Storage Mirroring file system (DTFS) driver.
DTFS is a transparent file system that monitors the storage file system so that
data changes can be captured. The data on those mount points can only be
replicated if they are under DTFS mount points. The DTSetup utility allows you
to configure entries in /etc/DT/dtfs_mounts to mount specific partitions as DTFS
when Storage Mirroring is started.
NOTE: Storage Mirroring is compatible with NFS and Samba services as long
as they are mounted on top of Storage Mirroring. Storage Mirroring
should be mounted just above the storage file system. Additionally,
NFS and/or Samba must be started after the Storage Mirroring
daemon.
Do not select the root as a replication mount point.
If you have a single drive system, mount DTFS to any of the
subdirectories directly under root that you want to replicate.
1.3.1.1. Add an entry to /etc/DT/dtfs_mounts—Type the path of the
highest subdirectory for which replication should be captured. This can
be the path to a mount point or a subdirectory of a volume. You can
either stop and restart the Storage Mirroring daemon so that new
entries in /etc/DT/dtfs_mounts will take effect or you can mount the
entries immediately using menu option 1.3.1.3.
NOTE: You will be prompted whether you want to replicate access
times. The access-time file property changes during a mirror
and causes replication operations to be generated during a
mirror and every time a file is read from or written to. This
may have a negative effect on performance. If you do not
replicate access times on both the source and target when
the volume is initially mounted, you may increase the
performance, especially during mirroring. (Access times
from files closes are always replicated regardless of this
configuration.)
1.3.1.2. Remove an entry from /etc/DT/dtfs_mounts—Type the path of
the entry that needs to be removed.
1.3.1.3. Mount all entries in /etc/DT/dtfs_mounts as DTFS—This option
will cause the entries of the list to be mounted with DTFS immediately,
rather than when the daemon is started. This allows you to review the
effects of the changes and troubleshoot any issues.
1.3.1.4. Unmount DTFS from all entries in /etc/DT/dtfs_mounts—This
will unmount DTFS from the mount points on the system, if any. This
allows you to make changes to the DTFS mounts without unloading the
daemon.
NOTE: If you are using Konquerer, you can only unmount a
replication mount point by rebooting the server.
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1.3.2. Configure Block Device Replication setup file—In order to use Storage
Mirroring replication, data that will be replicated on a block device must be
accessed through a loop device which is specially attached using the Storage
Mirroring loop driver (DTLOOP). DTLOOP allows the loop device to serve as a
monitoring point for operations performed on the block device so that data
changes can be captured. Existing block devices may be available for
replication, but the data on those block devices can only be replicated if they are
accessed through the DTLOOP loop device. It is important that operations on the
block device be made through the loop device only, or the operations will not be
replicated. Failure to do so will result in corrupted data on the target system.
1.3.2.1. Add an entry to /etc/DT/dtloop_devices—Enter the path to the
block device that is to be replicated and press Enter. Then, enter the
path to the loop device to use (/dev/loop#), if the same one should
always be attached. DTLOOP can also use the first one available, but
that may mean it attaches to a different one on subsequent
reboots/restarts, which may not be desirable. After pressing Enter, you
will be asked if you want to attach at an offset into the block device and
if you want to use an encrypted loop device. In general, these options
can be left blank. See the documentation for losetup for more
information on using encryption. You can either stop and restart the
Storage Mirroring daemon so that new entries in
/etc/DT/dtloop_devices will take effect or you can mount the entries
immediat
1.3.2.2. Remove an entry from /etc/DT/dtloop_devices—Enter the path of
ely usin
g menu option 1.3.2.3.
the block device that needs to be removed.
1.3.2.3. Attach all entries in /etc/DT/dtloop_devices to a loop device—
This option will cause the entries of the list to be attached to loop
devices with DTFS immediately, rather than when the daemon is
started. This allows you to review the effects of the changes and
troubleshoot any issues.
1.3.2.4. Detach loop devices from all entries in
/etc/DT/dtloop_devices—This option
device from the b
lock devices on the system, if any. This allows you to
will detach the DTLOOP loop
make changes to the DTLOOP loop devices without unloading the
daemon.
1.3.2.5. List block devices on this system—This option will provide a list of
block devices to which DTLOOP can be attached. Use this list as a guide
for menu option 1.3.2.1.
1.3.3. Manual Replication Configuration menu—This option will take you to the
menu where the file system and block device replication configuration can be
changed but not persisted between reboots/restarts.
1.3.3.1. Manually mount DTFS on a file system—Type the path of the
highest subdirectory for which replication should be captured. This can
be the path to a mount point or a subdirectory of a volume.
NOTE: You will be prompted whether you want to replicate access
times. The access-time file property changes during a mirror
and causes replication operations to be generated during a
mirror and every time a file is read from or written to. This
may have a negative effect on performance. If you do not
replicate access times on both the source and target when
the volume is initially mounted, you may increase the
performance, especially during mirroring. (Access times
from files closes are always replicated regardless of this
configuration.)
1.3.3.2. Manually unmount a DTFS file system—Type the path of the entry
that needs to be removed from replication.
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1.3.3.3. Manually attach DTLOOP to a block device—Enter the path to the
block device that is to be replicated and press Enter. Then, enter the
path to the loop device to use (/dev/loop#). DTLOOP can also use the
first one available. After pressing Enter, you will be asked if you want
to attach at an offset into the block device and if you want to use an
encrypted loop device. In general, these options can be left blank. See
the documentation for losetup for more information on using
encryption.
1.3.3.4. Manually detach DTLOOP from a block device—Enter the path of
the block device that needs to be removed from replication.
1.4. Configure iptables for Storage Mirroring—If you are using Storage Mirroring across
a router, you will need to configure the router ports to accommodate Storage Mirroring
traffic. Use this option to assist in IP address configuration.
1.4.1. Open Storage Mirroring ports in iptables—This option attempts to open the
IP ports needed by Storage Mirroring: 1500 (TCP/UDP), 1505 (UDP), and 1506
(TCP). This option only works on RedHat firewalls with a default configuration
and is provided for administrators who are not familiar with configuring
firewalls. If possible, you should open the port yourself.
1.4.2. Close Storage Mirroring ports in iptables—This option attempts to close the
ports that were opened in menu option 1.4.1.
1.5. Edit Storage Mirroring config file—Storage Mirroring program settings are the
user-definable options that control Storage Mirroring application settings and Storage
Mirroring processing settings. This includes options like the name of the verification log
file and the size of the Storage Mirroring memory pool. You can set these options using
DTSetup or the Storage Mirroring clients.
1.6. Configure Storage Mirroring driver performance—You can configure various
throttling and memory settings from DTSetup, although changes to these settings
should be made with caution. Contact technical support for advice on the proper
settings for your specific environment.
2. Start/Stop Storage Mirroring daemon—The Storage Mirroring daemon will start
automatically after Storage Mirroring is installed and the server is rebooted. You can start
and stop the Storage Mirroring daemon using this built-in DTSetup script.
2.1. Start Storage Mirroring and process driver config—This option starts the Storage
Mirroring daemon and the auto replication configuration is processed.
2.2. Stop Storage Mirroring but preserve driver config—This option stops the Storage
Mirroring daemon but does not unload the drivers from the kernel or detach and
unmount replicated devices.
2.3. Restart service but preserve driver config—This option does a full stop and start of
the Storage Mirroring daemon but does not unload the drivers from the kernel or
detach and unmount replicated devices.
2.4. Restart service and reset driver config—This option does a full stop and start,
completely unloading the daemon and drivers and then reloading them. Do not unload
the driver if there are still processes using the DTFS mount point.
2.5. Stop the running service and teardown driver config—This option stops the
Storage Mirroring daemon and the drivers are unloaded from the kernel after detaching
and unmounting replicated devices. Do not unload the driver if there are still processes
using the DTFS mount point.
2.6. Go to Replication Configuration menu—This option takes you to menu option 1.3.3
and then returns you to this point when exit that menu.
3. Start User Interface (DTCL -i)—You can launch the Storage Mirroring interactive command
prompt which allows you to enter DTCL commands one at a time.
4. Documentation/Troubleshooting tasks—This menu provides access to Storage Mirroring
log files, a diagnostic collection tool, user documentation, and several legal documents.
4.1. View log files—Storage Mirroring logs alerts, which are proccessing notifications,
warnings, and error messages. The logs are written to disk.
4.1.1. View /var/log/DT/dtlog*.dtl in less—This option uses the less file viewer
program to view all of the Storage Mirroring logs, starting from the most recent.
4.1.2. Follow the output of latest dtlog—This option uses tail -f to watch the output
of the Storage Mirroring logs in real-time.
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4.1.3. View /var/log/messages in less—This option uses the less file viewer
program to view the system log messages.
4.1.4. Follow the output of /var/log/messages—This option uses tail -f to watch
the output of the system log messages in real-time.
4.2. Collect and package diagnostic info—You may need to collect configuration data
when reporting problems to technical support. DTSetup can gather Storage Mirroring
log files, Storage Mirroring settings, network configuration information such as IP
addresses, and other data which may be necessary for technical support to
troubleshoot issues.
4.3. View user documentation—You can view Storage Mirroring documentation such as
the Evaluation Guide, User’s Guide, readme, and several legal documents. DTSetup
attempts to determine your viewers.
4.3.1. View ReadMe HTML—This option views the readme file which contains last
minute release notes.
4.3.2. View Scripting Guide PDF—This option views the Scripting Guide which
contains DTCL commands and scripting information.
4.3.3. View Users Guide PDF—This option views the User’s Guide which contains
instructions for using Storage Mirroring.
4.3.4. View Evaluation Guide PDF—This option views the Evaluation Guide which
contains step-by-step instructions for evaluating Storage Mirroring.
4.3.5. View End User License Agreement TXT—This option views the End User
License Agreement legal document.
4.3.6. View dtfs/dtrep module license TXT—This option views the open source
legal document.
4.3.7. Change a document viewer—This option allows you to specify a document
viewer.
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Installing or Upgrading the Storage Mirroring Client for Windows
Use the instructions to install the Storage Mirroring clients on a Microsoft Windows machine. Your
Windows version can be Windows 2003, Windows XP Service Pack 2 or later, or Windows Vista on
32-bit or 64-bit platforms.
1. Close any open applications.
2. Start the installation program using the appropriate instructions, depending on your media
source.
CD—Load the Storage Mirroring CD into the local CD-ROM drive. If auto-run is enabled, the
installation program will start automatically. To manually start the program, select Start, Run
and specify <cd_drive>:\autorun.exe. Select to install Storage Mirroring for Windows.
Web download—Launch the .exe file that you downloaded from the web. When prompted,
unzip the files and launch the installation.
3. When the Storage Mirroring installation program begins, the Welcome screen is displayed. Click
Next to continue.
4. Review and accept the Storage Mirroring license agreement to continue with the installation
program. Click Next to continue.
5. Select the folder where you would like to install the Storage Mirroring clients and click Next to
continue.
6. When you are ready to begin copying the files, click Install.
7. After the files have completed copying, click Finish to exit the installation program.
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Removing (Erasing) Storage Mirroring
Use these instructions if you want to remove (erase) an existing Storage Mirroring installation.
1. Go to a shell prompt by launching a terminal application from your graphical user interface (GUI)
or logging in via the Linux virtual console.
2. If you are not already, become the superuser ("root") by typing su -.
3. Erase Storage Mirroring by using the command rpm - e StorageMirroring.
A successful removal returns you to the shell prompt. If you receive an error message during the
removal, you will need to erase the software again. If you are unable to resolve the error, contact
technical support.
NOTE: After removing Storage Mirroring, some files may not be removed until after the server
has been rebooted
Removing the Storage Mirroring Client for Windows
Use these instructions if you want to remove the Storage Mirroring clients on a Microsoft Windows
machine.
NOTE: If desired, you can use the Add/Remove Programs function of the Windows Control Panel
to remove the Storage Mirroring clients.
1. Close any open applications.
2. Start the installation program using the appropriate instructions, depending on your media
source.
CD—Load the Storage Mirroring CD into the local CD-ROM drive. If auto-run is enabled, the
installation program will start automatically. To manually start the program, select Start, Run
and specify <cd_drive>:\autorun.exe. Select to install Storage Mirroring for Windows.
Web download—Launch the .exe file that you downloaded from the web. When prompted,
unzip the files and launch the installation.
3. When the Storage Mirroring installation program begins, the Welcome screen is displayed. Click
Next to continue.
4. On the Maintenance dialog box, select Remove and click Next to continue.
5. The installation program is immediately ready to begin removing the Storage Mirroring files.
Click Remove to continue.
When the message prompt informs you that the uninstall program has completed successfully, click
OK.
2 - 10
Clients
Storage Mirroring has two clients, the Management Console and the
Failover Control Center that control and manage your connections
and failover. Both clients can be started from the Windows
menu. You can also launch the Failover Control Center from the
menu in the Management Console.
NOTE: Storage Mirroring also has a scripting language which can be used in an interactive client
or in scripts. For more information, see the Scripting Guide.
Management Console
From the Management Console, you can manage, monitor, and control your Storage Mirroring
connections. The Management Console is a two pane view. The views in the panes change depending
on what is highlighted. For example, when the root of the tree in the left pane is selected, all of the
machines in your environment running Storage Mirroring are displayed in the right pane. If you
expand the tree in the left pane and select a server, any connections for that server are displayed in
the right pane.
Start
Tools
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