Compaq StorageWorks 4000 - RAID Array, 4000 Technology Brief
Technology Brief
June 1999
ECG0205699A
Prepared by ECG Technology
Communications Group
Compaq Computer Corporation
Contents
Introduction............................... 3
Hardware Technology ............... 4
StorageWorks RAID Array
4000........................................ 4
StorageWorks RAID Array
4000 Controllers....................... 5
Compaq StorageWorks Fibre
Channel Host Adapter.............. 7
StorageWorks Fibre Channel
Storage Hub 7.........................10
StorageWorks Fibre Channel
Storage Hub 12.......................10
Gigabit Interface Converters....11
Cables....................................12
Hardware Architecture .............12
Firmware...................................14
Operating Systems
Supported.................................15
Redundant Operating
Systems Supported.................15
Non-redundant Operating
Systems Supported.................15
Compaq Utilities.......................16
Array Configuration Utility........16
Fibre Fault Isolation Utility .......17
User Diagnostics Utility............18
Array Diagnostics Utility...........19
Compaq Insight Manager........19
Compaq Redundancy
Manager for Microsoft
Windows NT...........................19
Performance.............................20
Migration to RA4000 from
SCSI Technology......................21
Clustering with RA4000............22
For More Information................22
APPENDIX A: User
Diagnostics Utility ....................23
Compaq RAID Array 4000
Overview
Abstract: The Compaq StorageWorks RAID Array 4000 (RA4000),
formerly the Fibre Channel Storage System, is an external storage
solution incorporating Fibre Channel interconnect technology. This
solution overcomes inherent limitations of small computer systems
interface (SCSI) interconnect technology. Fibre Channel interconnect
technology is designed to satisfy the requirements of such enterprise
applications as databases, data marts, email, groupware, Web
servers, and file and print for large storage capacity and scalable
input/output (I/O) performance.
The architecture of this Fibre Channel storage solution enables
administrators to simultaneously achieve multiple goals:
• To provide hardware redundancy and failover capabilities with
no single point of failure (NSPOF).
• To build a scalable external storage solution for high capacity or
high growth applications by:
• Scaling a single I/O slot to more than 3.2 TB.
• Scaling an 8-PCI-slot server to more than 25.6 TB.
• To scale cache and processing power for increased I/O
performance.
• To conserve I/O slots for connecting other types of I/O devices.
This technology brief explains the hardware components, hardware
architecture, firmware functionality, software support, and
performance expectations for the RA4000.
Compaq RAID Array 4000 Overview 2
ECG0205699A
Notice
The information in this publication is subject to change without notice and is provided “AS IS” WITHOUT
WARRANTY OF ANY KIND. THE ENTIRE RISK ARISING OUT OF THE USE OF THIS
INFORMATION REMAINS WITH RECIPIENT. IN NO EVENT SHALL COMPAQ BE LIABLE FOR
ANY DIRECT, CONSEQUENTIAL, INCIDENTAL, SPECIAL, PUNITIVE OR OTHER DAMAGES
WHATSOEVER (INCLUDING WITHOUT LIMITATION, DAMAGES FOR LOSS OF BUSINESS
PROFITS, BUSINESS INTERRUPTION OR LOSS OF BUSINESS INFORMATION), EVEN IF
COMPAQ HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
The limited warranties for Compaq products are exclusively set forth in the documentation accompanying
such products. Nothing herein should be construed as constituting a further or additional warranty.
This publication does not constitute an endorsement of the product or products that were tested. The
configuration or configurations tested or described may or may not be the only available solution. This test
is not a determination or product quality or correctness, nor does it ensure compliance with any federal,
state, or local requirements.
Product names mentioned herein may be trademarks and/or registered trademarks of their respective
companies.
Compaq, Contura, Deskpro, Fastart, Compaq Insight Manager, LTE, PageMarq, Systempro, Systempro/LT,
ProLiant, TwinTray, ROMPaq, LicensePaq, QVision, SLT, ProLinea, SmartStart, NetFlex, DirectPlus,
QuickFind, RemotePaq, BackPaq, TechPaq, SpeedPaq, QuickBack, PaqFax, Presario, SilentCool,
CompaqCare (design), Aero, SmartStation, MiniStation, and PaqRap are registered with the United States
Patent and Trademark Office.
Netelligent, Armada, Cruiser, Concerto, QuickChoice, ProSignia, Systempro/XL, Net1, LTE Elite,
Vocalyst, PageMate, SoftPaq, FirstPaq, SolutionPaq, EasyPoint, EZ Help, MaxLight, MultiLock,
QuickBlank, QuickLock, UltraView, Innovate logo, Wonder Tools logo in black/white and color, and
Compaq PC Card Solution logo are trademarks and/or service marks of Compaq Computer Corporation.
Microsoft, Windows, Windows NT, Windows NT Server and Workstation, and Microsoft SQL Server for
Windows NT are trademarks and/or registered trademarks of Microsoft Corporation.
NetWare and Novell are registered trademarks and intraNetWare, NDS, and Novell Directory Services are
trademarks of Novell, Inc.
Pentium is a registered trademark of Intel Corporation.
Copyright ©1999 Compaq Computer Corporation. All rights reserved. Printed in the U.S.A.
Compaq RAID Array 4000 Overview
Technology Brief prepared by ECG Technology Communications Group
First Edition (June 1999)
Document Number ECG0205699A
Compaq RAID Array 4000 Overview 3
ECG0205699A
Introduction
Note: This paper includes the terms fibre and fiber. Fibre is the international spelling that refers
to the Fibre Channel Standards that include optical and copper media. Fiber refers to the optical
media used to implement Fibre Channel.
Applications central to enterprise operations demand remarkable storage capacity and scalable
performance. Data marts, for example, may grow by as much as 400 percent per year. Email data
and Lotus Notes data typically double each year. Databases and consolidated print and file
applications also demand increasing storage capacity. With its inherent I/O and physical
limitations, SCSI technology cannot support the scalability of storage capacity and I/O
performance required by such applications.
The expanding need for enterprise storage capacity and performance demands new storage
solutions. After extensively studying possible alternatives, Compaq has determined that Fibre
Channel is the best interconnect technology to propel growth of enterprise storage. As a result,
Compaq actively participates in industry standardization efforts for Fibre Channel interconnect
technology and is continuing to develop products incorporating that technology.
The RA4000 is a primary storage solution incorporating Fibre Channel technology. The Fibre
Channel architecture of this solution enables administrators to scale the storage capacity
supported by a single, 8 PCI-slot server from gigabytes to more than 25.6 TB, while
simultaneously scaling cache, processing power, and throughput of their storage subsystem.
The RA4000 is an external array storage system which means the array controller is housed in the
hard disk drive (HDD) instead of the server. This design enables clustering and NSPOF
configurations that allows the enterprise to reduce its planned and unplanned downtime.
Unplanned system downtime, which usually is caused by component failure, can be significantly
reduced by using RAID and redundant components. Planned downtime, such as planned
maintenance or system expansion, also can be reduced with the RA4000 solution.
Features of the RA4000 include:
• Online capacity expansion
• Hot growth
• Hot add (Novell)
• PCI hot-plug support
• The connectivity benefits of Fibre Channel technology
1
The RA4000 solution provides enterprises with increased availability, scalability in both
performance and capacity, and a tight integration with ProLiant servers. This leap in capacity,
scalability, and availability results from innovations to proven Compaq hardware and software
products and from total storage system integration. The RA4000 targets computing environments
that require large, rapidly growing storage capacity and scalable I/O performance.
This technology brief will explain the hardware components, hardware architecture, firmware
functionality, software support, and performance expectations for the RA4000.
1
It is easier to add storage in rack configurations.
Compaq RAID Array 4000 Overview 4
ECG0205699A
Hardware Technology
The RA4000 consists of 11 hardware components that can be interconnected to form a Fibre
Channel Arbitrated Loop (FC-AL) topology:
• Compaq StorageWorks RAID Array 4000
• Compaq StorageWorks RAID Array 4000 Controller
• Compaq StorageWorks RAID Array 4000 Redundant Controller
2
• Compaq StorageWorks Fibre Channel Host Adapter/E
• Compaq StorageWorks Fibre Channel Host Adapter/P
• Compaq StorageWorks Fibre Channel Storage Hub 7
• Compaq StorageWorks Fibre Channel Storage Hub 12
• Short wave gigabit interface converters
• Long wave gigabit interface converters
• Multi-Mode Fibre Channel Cables
• Single-Mode Fibre Channel Cables
StorageWorks RAID Array 4000
This section describes the function of each hardware component and then explains the hardware
architecture and Fibre Channel topology used in the RA4000.
An RA4000 is an external drive enclosure containing:
• A high-performance RA4000 Controller.
• An optional RA4000 Redundant Controller.
• A hot-pluggable fan assembly.
• Optional redundant hot-pluggable power supplies.
The RA4000 is available in a tower or a 4U rack form factor and supports hot-pluggable drives.
The RA4000 enhances the availability of data through redundant controllers that can be deployed
in an NSPOF storage system.
2
The redundant controller is an RA4000 Controller with redundancy support firmware.
Compaq RAID Array 4000 Overview 5
ECG0205699A
A single RA4000 accommodates up to eight 1.6-inch or twelve 1-inch Wide-Ultra SCSI-3,
Fast-Wide SCSI-2 or Fast SCSI-2 drives. As Table 1 shows, a single, fully populated RA4000
can provide a total capacity of up to 291.2 GB using eight hard disk drives. For installations in
which improved performance (spindle density for example) is more important than maximum
capacity, 12 hard drives placed in an RA4000 can provide up to 218.4 GB of capacity.
Table 1. Storage capacity of a single Compaq StorageWorks RAID Array 4000
Maximum Total Capacity (gigabytes)
Maximum
Number of
Drives
Drive Size
(inches)
Native Capacity
per Drive
(gigabytes) RAID 0 RAID 1 RAID 4 or 5
8 1.6 36.4 291.2 145.6 254.8
8 1.6 18.2 145.6 72.8 127.4
8 1.6 9.1 72.8 36.4 63.7
12 1.0 18.2 218.4 109.2 200.2
12 1.0 9.1 109.2 54.6 100.1
12 1.0 4.3 51.6 25.8 47.3
StorageWorks RAID Array 4000 Controllers
The RA4000 Controller is an intelligent Fibre Channel-to-SCSI array3 controller integrated into
the RA4000 solution. The controller is based on the Compaq SMART-2 architecture and has two
Wide-Ultra SCSI-3 channels. Each channel can transfer data at 40 megabytes per second (MB/s)
for a total of 80 MB/s possible internal bandwidth. The array controller-to-host interface is Fibre
Channel for high-speed connection to the server. The Fibre Channel interface can transfer data to
the server at burst rates of 100 MB/s.
The RA4000 Controller:
• Supports RAID4 0, 0+1, 1, 4, and 5.
• Supports multiple logical drives and online capacity expansion within the array.
• Features sixth-generation Compaq RAID technology and components.
• Can have a total of 64 MB of usable cache (16 MB read and 48 MB user-selectable
read/write). The cache is scalable up to 5.6 GB in an 8-slot, single server environment.
The RA4000 Redundant Controller is the same controller as the standard RA4000 controller with
redundancy support firmware embedded that adds higher availability not found previously in
Compaq storage systems. The RA4000 Redundant Controller fully supports Compaq Insight
Manager, Pre-Failure Warranty, and Fibre Channel Host Adapter failover.
The RA4000 Controller and RA4000 Redundant Controller supports Wide-Ultra SCSI-3,
Fast-Wide SCSI-2, or Fast SCSI-2 drives. Use of SCSI technology inside the RA4000 allows
customers to use existing SCSI disk drives. Since hard disk drives are the most costly part of a
storage system, this compatibility can reduce the cost of implementing an RA4000.
3
An array is a set of disk drives that are physically grouped together and can be subdivided into logical drives consisting of one or
more disks in the set.
4
Redundant Array of Independent Disks. RAID levels are methods that improve array performance and provide for protection of the
data on disks.
Compaq RAID Array 4000 Overview 6
ECG0205699A
Hot-Swapping Disk Drives
The RA4000 Controller supports individual failed disk drives to be removed from an RA4000
and replaced them while the array is active. After the new drive is installed, the Compaq
Automatic Data Recovery software automatically rebuilds data on the new drive without
administrator intervention.
Online Capacity Expansion
The RA4000 Controller supports adding disk drives to an RA4000 and redistributing the data
across the drives in the array while the array is active. Note, however, that to add an additional
RA4000 to the overall storage system, reboot the server.
Array Accelerator
Each RA4000 Controller installed in an RA4000 includes an enhanced Array Accelerator with a
total of 64 MB of cache. Of that total, 16 MB is dedicated read cache that is integrated on the
base controller board. The remaining 48 MB is user-configurable5, battery-backed read/write
cache located on a small, removable board that plugs into the base controller board.
For owners of the original Fibre Channel Storage System Controller with 32 MB of cache,
Compaq offers a memory upgrade that expands the total memory available to 64 MB. 16 MB of
dedicated read cache remains integrated on the original base controller board. The 48 MB
memory upgrade is a user-configurable, battery-backed board. The default allocation of this
memory cache is 50 percent read and 50 percent write. The user can configure the cache using the
Array Configuration Utility.
An RA4000 Redundant Controller (64-MB cache) can be added to an existing Fibre Channel
Storage System (32-MB cache). In this configuration, all write-cache is disabled and performance
in certain write-intensive environments may be affected. Compaq recommends the memory
upgrade kit in these types of environments.
The RA4000 Controller uses a posted write-caching scheme that allows applications to continue
without waiting for write operations to complete. Without this type of caching, the controller
would be forced to wait until the write data is actually written to the disk before returning
completion status to the operating system.
With write-back caching, the controller can post-write data to high-speed cache memory and
immediately return completion status to the operating system. The write operation is completed in
microseconds rather than milliseconds. Data in the write cache is written to disk later, at an
optimal time for the controller.
While data is in the write cache, it is protected against memory chip failure by Error Checking
and Correcting (ECC) technology and against system power loss by integrated battery backup.
The removable dynamic random access memory (DRAM) with integrated battery keeps
posted-write data secure in the unlikely event that power should be lost or the base controller
board should fail.
Should a system power outage occur while write data is stored in the cache, the data is protected
for at least four days by power from the battery backup system.
5
Configure cache memory using the Compaq Array Configuration Utility. Refer to “Array Configuration Utility” later in this
document.
Compaq RAID Array 4000 Overview 7
ECG0205699A
Once system power is restored, the posted-write data will automatically be written to disk. Should
the base controller board fail, the small write cache board can be removed and installed on a
replacement base controller board, and the posted-write data will automatically be written to disk.
The 16-MB read-ahead cache integrated on the RA4000 Controller uses an intelligent read-ahead
algorithm that anticipates data needs and reduces latency. The algorithm detects sequential read
activity on single or multiple I/O threads and predicts that sequential read requests will follow.
The algorithm then reads data from the disk drives before the data is actually requested. When the
read request occurs, the data is serviced out of the high-speed cache memory at microsecond
speeds rather than from the disk drive at millisecond speeds.
When the firmware detects non-sequential read activity, the read-ahead feature is automatically
disabled. This adaptive read-ahead scheme provides excellent performance for sequential small
block read requests. At the same time, it avoids degradation of random read performance.
The ECC technology used on the Array Accelerator provides greater data protection than
mirroring and is much more cost effective. The ECC scheme generates 16 bits of check data for
every 64 bits of user data. This check data can be used to detect and correct errors. ECC can be
used to detect and correct DRAM bit errors, DRAM chip failures, and memory bus errors on the
Array Accelerator connector.
Compaq StorageWorks Fibre Channel Host Adapter
The Fibre Channel Host Adapter is available in either a PCI version or an EISA6 version. The
Fibre Channel Host Adapter/P is a PCI bus master device. The Fibre Channel Host Adapter/E is
for use in a server equipped only with an EISA expansion bus or with a server that has a majority
of EISA bus slots. It takes advantage of the EISA architecture by performing 32 bit bus master
burst transfers. Both the PCI and EISA versions of the Fibre Channel Host Adapter require
installation of a gigabit interface converter (GBIC) into the I/O port before the multi-mode fiber
cable is connected.
In single adapter environments, the server can be connected directly to the RA4000 or multiple
RA4000s using a storage hub. There are no redundant paths to ensure data availability in this
configuration should a component fail.
Figure 1 through Figure 4 depict examples of some possible RA4000 configurations. For more
detailed information, refer to the appropriate RA4000 manuals.
Using custom-length, 50-micron multi-mode cables, interconnect distances between components
can be up to 500 meters. Therefore, RA4000s can be located up to 1 kilometer from the Fibre
Channel Host Adapter. Using custom-length 9-micron single-mode cables, interconnect distances
between components can be up to 10 kilometers. Therefore, RA4000s can be located up to
20 kilometers from the Fibre Channel Host Adapter.
6
Extended Industry Standard Architecture.
Loading...