HP ProLiant 2500 Disk Subsystem Performance and Scalability

HP ProLiant 2500 Manual

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  • HP ProLiant 2500 | Disk Subsystem Performance and Scalability - Page 1
    WHITE PAPER [September 1997] Prepared By Microsoft Windows NT Integration Team Compaq Computer Corporation CONTENTS Disk Subsystem Overview 3 Disk-Related Performance Characteristics 4 Like Drive Scalability 17 Like Capacity Scalability 19 Disk Controller Scalability 24 Performance Measurement
  • HP ProLiant 2500 | Disk Subsystem Performance and Scalability - Page 2
    service marks of Compaq Computer Corporation. Other product names mentioned herein may be trademarks and/or registered trademarks of their respective companies. Copyright ©1997 Compaq Computer Corporation. All rights reserved. Printed in the U.S.A. Microsoft, Windows, Windows NT, Windows NT Server
  • HP ProLiant 2500 | Disk Subsystem Performance and Scalability - Page 3
    one and two controller test configurations that were used in the Compaq ProLiant 5000 during testing. Table 1: Disk Subsystem Testing Environment Environment Equipment Used Server Hardware Platform Compaq ProLiant 5000 Memory 128 MB Processors (4) P6/200 MHz 512k secondary cache Network
  • HP ProLiant 2500 | Disk Subsystem Performance and Scalability - Page 4
    Table 1: (cont.) Disk Subsystem Testing Environment Environment Equipment Used Server Software Configuration Microsoft Windows NT Server version 4.0 Service Pack 2 Compaq Support Software Diskette 1.20A Client Configuration Compaq Deskpro 575 Netelligent 10/100 TX PCI UTP Controller and MS
  • HP ProLiant 2500 | Disk Subsystem Performance and Scalability - Page 5
    ECG025.0997 WHITE PAPER (cont.) ... Table 2: (cont.) Disk Performance Measurement Terms Terms Description Latency The time required for the disk to spin one complete revolution. Average Latency The time required for the disk to spin half a revolution. Average Access Time The average length
  • HP ProLiant 2500 | Disk Subsystem Performance and Scalability - Page 6
    ECG025.0997 WHITE PAPER (cont.) ... One method to decrease seek time is to distribute data across multiple drives. For instance, the initial configuration in Figure 1 shows a single disk containing data. The new configuration reflects the data being striped across multiple disks. This method
  • HP ProLiant 2500 | Disk Subsystem Performance and Scalability - Page 7
    on the market could spin at approximately 3600 RPMs. As the market demand for better system performance increased, disk manufacturers responded by supplying faster spin rates for hard disks. By producing faster spinning disks, manufacturers reduced the amount of overall access time. Average latency
  • HP ProLiant 2500 | Disk Subsystem Performance and Scalability - Page 8
    WHITE PAPER (cont.) Note: Remember that the disks used in Figure 2 are identical in size and RAID configuration. ECG025.0997 ... However, be aware that the average latency time might not always decrease when adding more drives to your system. For example, in Figure 2 - Example 2, the new
  • HP ProLiant 2500 | Disk Subsystem Performance and Scalability - Page 9
    ECG025.0997 WHITE PAPER (cont.) ... Average Access Time Average access time is simply described as average seek time plus latency. What this equates to is the amount of time the disk has to seek to find the data plus the time it takes for the disk to spin under the head. For example, Figure 3
  • HP ProLiant 2500 | Disk Subsystem Performance and Scalability - Page 10
    , which then passes the data to the Host Bus and then on to the server. If one hard disk transfers at 5 MB/s, the SCSI channel transfers at 40 Bus (Memory) transfer rate PCI Bus transfers 3 to/from the Host Bus Dual Inline Memory Module (DIMM) 4 Host Bus transfers to/from ProLiant 5000
  • HP ProLiant 2500 | Disk Subsystem Performance and Scalability - Page 11
    Disk drives have a special interface used to communicate with the SCSI bus. This interface, defined in disk drive characteristic specification documents, identifies the type of controller the drive supports not the transfer rate of the disk. For example, if you are using a Wide-Ultra drive you know
  • HP ProLiant 2500 | Disk Subsystem Performance and Scalability - Page 12
    greater than the SCSI channel. Disk Controller Transfer Rates Disk controllers are continuously being upgraded to support wider data paths and faster transfer rates. Currently, Compaq supports three industry standard SCSI interfaces on their disk controllers, as shown in Table 5. Controller Name
  • HP ProLiant 2500 | Disk Subsystem Performance and Scalability - Page 13
    Supported on the ProLiant 5000, 6000, 6500 and 7000) A system I/O bus architecture specification that supports 32-bit bus-mastered data. Designed to support it would take a minimum of three Compaq Wide-Ultra SCSI Controllers running at their data in memory, also known as Random Access Memory (RAM),
  • HP ProLiant 2500 | Disk Subsystem Performance and Scalability - Page 14
    disk drive (refer to Figure 4 for reference). The system first tries to complete the READ request by retrieving the data from the file system cache (memory). If it is not there, the system has to retrieve the data from the hard disk. Figure 5 shows the communications that take place to retrieve
  • HP ProLiant 2500 | Disk Subsystem Performance and Scalability - Page 15
    . ECG025.0997 ... Table 7 lists the Host bus transfer rates for the following Compaq servers: Table 7: Host Bus (Memory) Transfer Rates Server Name Transfer Rate ProLiant 5000, 6000, 6500 and 7000 540 MB/s ProLiant 1500, 2500 and 4500 267 MB/s The last example discussed how READ performance
  • HP ProLiant 2500 | Disk Subsystem Performance and Scalability - Page 16
    comes across the SCSI Bus asking the disk drive to retrieve some information. The disk drive retrieves then sends the requested data back to the server via the SCSI bus. The time it takes to complete this process seems to be acceptable at first glance until you examine the amount of
  • HP ProLiant 2500 | Disk Subsystem Performance and Scalability - Page 17
    ECG025.0997 WHITE PAPER (cont.) ... Concurrency is very effective in a multi-drive environment because, while one drive is retrieving data, another request can be coming across the SCSI bus as shown in Figure 7. When using multiple drives, each drive can send data across the SCSI bus as soon as it
  • HP ProLiant 2500 | Disk Subsystem Performance and Scalability - Page 18
    server configuration for your environment, yet leave slots available for future disk controllers that might be necessary to support more drives out weigh the performance gain?". To answer this question, Compaq tested controllers using the same RAID configuration and added drives, then measured
  • HP ProLiant 2500 | Disk Subsystem Performance and Scalability - Page 19
    because you have more drives processing disk requests. Using smaller size drives limits your maximum capacity per controller. For example, the Compaq SMART-2 Array Controller supports up to 14 drives. By using fourteen 2GB drives, your data capacity equals 28GB. By using fourteen 4GB drives, your
  • HP ProLiant 2500 | Disk Subsystem Performance and Scalability - Page 20
    our single disk controller like capacity tests provide evidence that support our theory on concurrency. For example, if you need beneficial in this configuration. Like Capacity Scaling (RAID 0 - 1 Controller) 16,000,000 Server Throughput (Bytes/sec) 14,000,000 12,000,000 10,000,000 4 x 2GB 2
  • HP ProLiant 2500 | Disk Subsystem Performance and Scalability - Page 21
    of this configuration. By having twelve lower capacity drives, you are limiting the maximum disk capacity on that controller. Like Capacity Scaling (RAID 0 - 1 Controller) Server Throughput (Bytes/sec) 20,000,000 18,000,000 16,000,000 14,000,000 12,000,000 10,000,000 8,000,000 6,000,000 4,
  • HP ProLiant 2500 | Disk Subsystem Performance and Scalability - Page 22
    ECG025.0997 WHITE PAPER (cont.) ... Like Capacity Scaling (RAID 5 - 1 Controller) 14,000,000 12,000,000 10,000,000 7+1 x 2GB 3+1 x 4GB Server Throughput (Bytes/sec) 8,000,000 6,000,000 54% 4,000,000 2,000,000 0 4 8 16 20 24 28 32 36 40 44 48 52 56 57 Number
  • HP ProLiant 2500 | Disk Subsystem Performance and Scalability - Page 23
    12,000,000 10,000,000 8,000,000 28% 11+1 x 2GB 5+1 x 4GB 2+1 x 9GB Server Throughput (Bytes/sec) 6,000,000 4,000,000 2,000,000 0 4 8 16 20 24 28 32 36 your maximum capacity per controller. For example, the Compaq SMART-2 Array Controller supports up to 14 drives. By using fourteen 2GB
  • HP ProLiant 2500 | Disk Subsystem Performance and Scalability - Page 24
    ECG025.0997 WHITE PAPER (cont.) ... Summary of Findings - Like Capacity Scaling Our test results conclude that by doubling the number of drives in a system, regardless of the data storage capacity requirements and the fault tolerance used, we consistently received an improvement in performance.
  • HP ProLiant 2500 | Disk Subsystem Performance and Scalability - Page 25
    , yielding a 57% increase in system performance. 20,000,000 18,000,000 16,000,000 Disk Controller Scaling (RAID 5) 10+2 x 4GB, 2 Ctr 11+1 x 4GB, 1 Ctr Server Throughput (Bytes/sec) 14,000,000 12,000,000 10,000,000 8,000,000 6,000,000 4,000,000 57% 2,000,000 0 4 8 16 20 24 28
  • HP ProLiant 2500 | Disk Subsystem Performance and Scalability - Page 26
    ECG025.0997 WHITE PAPER (cont.) ... Disk Controller Scaling (RAID 0) Server Throughput (Bytes/sec) 20,000,000 18,000,000 16,000,000 14,000,000 12,000,000 10,000,000 8,000,000 6,000,000 4,
  • HP ProLiant 2500 | Disk Subsystem Performance and Scalability - Page 27
    Compaq server hardware. These tools are now available on the Compaq Resource Paq for Microsoft Windows NT. To obtain a copy of the Compaq Resource Paq, go to the Compaq Tools Description Exercises the memory, disk and network resources of your system. Exercises memory access, caching and paging
  • HP ProLiant 2500 | Disk Subsystem Performance and Scalability - Page 28
    Power Supply. These counters require Compaq Support Software Version 1.21a or later for Microsoft Windows NT and Compaq Insight Manager 3.30 or later. NetFlex-3/Netelligent Performance Monitor Adds a new object, called Compaq NetFlex-3 Network Driver Table 13, as a guide in deciding which method is
  • HP ProLiant 2500 | Disk Subsystem Performance and Scalability - Page 29
    ) This configuration of mirrored sets of data uses 50 percent of drive storage capacity to provide greater data reliability by storing a duplicate of all user data on a separate disk drive. Therefore, half of the drives in the array are duplicated or "mirrored" by the other half. This RAID level
  • HP ProLiant 2500 | Disk Subsystem Performance and Scalability - Page 30
    likely of all the disk subsystem components to be a performance bottleneck. If this device did become a bottleneck, however, simply add more memory to the server. This is a great way to improve disk subsystem performance. Benefits of Scaling Throughout this paper we learn through many examples that
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W
HITE
P
APER
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ECG025.0997
[September 1997]
Prepared By
Microsoft Windows NT
Integration Team
Compaq Computer
Corporation
C
ONTENTS
Disk Subsystem
Overview
.....................
3
Disk-Related
Performance
Characteristics
............
4
Like Drive
Scalability
.................
17
Like Capacity
Scalability
.................
19
Disk Controller
Scalability
.................
24
Performance
Measurement Tools... 27
Preventing Data
Loss while
Maintaining
Performance
..............
28
Disk Subsystem
Summary of
Findings
....................
29
Disk Subsystem Performance and
Scalability
In today's networking environments, the disk subsystem is a key element in determining
overall system performance.
The goal of this paper is to provide informative test results
and performance-related information for various disk subsystems, to assist systems
engineers and network administrators in making decisions on disk subsystem installation,
optimization, and configuration.
This white paper also provides information on using Fault Tolerance to prevent data loss,
while maintaining system performance.
Finally, this paper provides a section discussing
the advantages and disadvantages of RAID technology.