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    • Abstract: Technical ReportUsing Flash Cache for Exchange 2010Wei Liu, NetAppSeptember 2010 | TR-3867EXECUTIVE SUMMARY®This technical report describes the benefits of the Flash Cache (formerly PAM II) for Microsoft

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Technical Report
Using Flash Cache for Exchange 2010
Wei Liu, NetApp
September 2010 | TR-3867
EXECUTIVE SUMMARY
®
This technical report describes the benefits of the Flash Cache (formerly PAM II) for Microsoft
Exchange 2010 workload. Specifically, a 256GB Flash Cache card in a FAS3140 controller doubled total
achieved I/O per second (IOPS), increased Exchange 2010 mailboxes supported by 67%, and increased
storage use by 67%.
TABLE OF CONTENTS
1 INTRODUCTION ......................................................................................................................... 3
2 TEST CONFIGURATION ............................................................................................................ 3
2.1 SIMULATED EXCHANGE CONFIGURATION............................................................................................. 3
2.2 FAS3140 CONFIGURATION ....................................................................................................................... 4
3 RESULTS AND ANALYSIS ........................................................................................................ 4
3.1 TOTAL ACHIEVED DB IOPS ...................................................................................................................... 4
3.2 NUMBER OF MAILBOXES SUPPORTED................................................................................................... 5
3.3 STORAGE USE COMPARISON .................................................................................................................. 5
4 CONCLUSIONS .......................................................................................................................... 6
APPENDIX: FAS3140 CONFIGURATION ....................................................................................... 6
REFERENCES .................................................................................................................................. 7
ACKNOWLEDGEMENTS ................................................................................................................. 7
2 Using Flash Cache for Exchange 2010
1 INTRODUCTION
Microsoft Exchange 2010 includes several improvements to support larger mailboxes at lower cost. For
example, a typical Exchange 2010 mailbox size is expected to be greater than 1GB, while generating ~0.10
input/output operations per second (IOPS), compared to ~0.30 to 0.40 IOPS for Exchange 2007. This
reduced level of I/O operations presents the option to use low-cost SATA disks [1] with Exchange 2010.
®
NetApp Flash Cache (formerly PAM II) reduces costs for storage, power, and rack space by optimizing the
performance of random read-intensive workloads such as file services, messaging, virtual infrastructure, and
OLTP databases [2].
The purpose of this technical report is to quantify the benefits of Flash Cache for Exchange 2010 by running
Jetstress 2010 tests on a NetApp FAS3140 storage system with SATA disks.
2 TEST CONFIGURATION
The testbed was configured with two IBM x3650 servers (four processors at 2.66GHz, 18GB RAM) and a
NetApp FAS3140 storage system. The servers and FAS3140 were connected using 4Gbps Fibre Channel
links (two per server) by way of a pair of Brocade switches.
Jetstress 2010 was used to simulate Exchange 2010 mailboxes and test the performance of storage
subsystems. The software versions used by the two IBM servers are:
• Windows Server 2008 Enterprise SP2
• Jetstress version: 14.01.0043.000
• ESE.dll version: 14.00.0639.019
2.1 SIMULATED EXCHANGE CONFIGURATION
Table 1 summarizes the simulated Exchange 2010 configurations for both Flash Cache enabled and
disabled. The mailbox size, 2000MB, was kept the same whether Flash Cache was enabled or disabled.
With Flash Cached enabled, more IOPS per mailbox can be supported, and a higher number of threads per
database (six instead of five) were used to drive more load against the FAS3140. The number of simulated
mailboxes was also higher when Flash Cache was enabled than when it was disabled. This parameter was
mainly determined by trying to simulate as many mailboxes as possible, while maintaining the database
read and write latencies below 20msec, as required by Microsoft. Section 3, “Results and Analysis,”
describes the details. In all tests, the background database maintenance was enabled 24x7 in keeping with
the Microsoft recommendation.
Table 1) Summary of simulated Exchange 2010 configurations.
Parameters Flash Cache Disabled Flash Cache Enabled
Simulated mailbox size (MB) 2,000 2,000
Number of IOPS simulated per mailbox 0.12 0.15
Number of threads per database 5 6
Background database maintenance 24x7 24x7
Number of servers under test 2 2
3 Using Flash Cache for Exchange 2010
2.2 FAS3140 CONFIGURATION
The FAS3140 storage system is simple to deploy and to manage. It ships with a wealth of integrated data
®
protection and management software based on Data ONTAP to help increase storage use and efficiency
[3]. For the tests described in this technical report, the FAS3140 was running Data ONTAP 7.3.2. Standard
® ®
NetApp features such as Snapshot™, FlexVol flexible volumes, and RAID-DP were used.
RAID-DP is a high-performance implementation of RAID 6 that provides double parity across the disk
subsystem and protects against the failure of up to two disks per RAID group. Calculations have shown that
double-parity RAID offers more than 160 times the protection against data loss than RAID 10 and almost
4,000 times the protection against data loss of RAID 5 [4]. The test results described in this report were
obtained with RAID-DP in action.
Table 2 summarizes the FAS3140 configuration common to tests with Flash Cache enabled and disabled.
The appendix contains FAS3140 configuration details.
Table 2) Summary of FAS3140 configuration.
Parameters FAS3140 Configuration
Data ONTAP version 7.3.2
Hard disk drive (HDD) type SATA, 1TB, 7.2K RPM
Number of HDDs 64
RAID level RAID-DP
The FAS3140 had one Flash Cache (256GB) module installed. Except for the following settings, the default
Flash Cache settings were used:
• Without Flash Cache: flexscale.enable off
• With Flash Cache: flexscale.enable on
The Jetstress performance test was run first without Flash Cache to establish the baseline. Then, the same
test was run again with Flash Cache enabled.
3 RESULTS AND ANALYSIS
This section describes the test results in terms of total achieved database IOPS, number of mailboxes
supported, and storage capacity use. All of the test results described here satisfy Microsoft’s latency
requirement, that is, less than 20msec for both read and write average latencies [5].
3.1 TOTAL ACHIEVED DB IOPS
Figure 1 shows the total achieved database IOPS, including both transactional database reads and writes.
The total achieved database IOPS was 929 with Flash Cache disabled and 1,964 with Flash Cache enabled.
The total achieved database IOPS was 111% higher when Flash Cache was enabled. This improvement
had two sources:
• Increased number of IOPS per mailbox
• Increased number of supported mailboxes (see section 3.2)
4 Using Flash Cache for Exchange 2010
Figure 1) Total achieved database IOPS (higher is better).
3.2 NUMBER OF MAILBOXES SUPPORTED
Figure 2 shows the number of mailboxes supported:
• 7,200 when Flash Cache was disabled
• 12,000 when Flash Cache was enabled
With the same number of hard disk drives, 67% more mailboxes were supported due to Flash Cache.
Figure 2) Number of mailboxes supported (higher is better).
3.3 STORAGE USE COMPARISON
Storage capacity use, or storage use, measures the percentage of available storage capacity that contains
user data. The same set of hard disk drives was used for both tests with Flash Cache disabled and enabled;
therefore, a valid comparison can be drawn using the total database sizes in both tests, as shown in
Figure 3.
5 Using Flash Cache for Exchange 2010
Figure 3) Total database sizes (higher is better).
The total database sizes are:
• 13.733TB with Flash Cache disabled
• 22.888TB with Flash Cache enabled
The increase in total database size is 67%, due to the number of additional mailboxes supported with Flash
Cache. Given the same raw disk capacity, this translates to 67% higher storage use when Flash Cache is
enabled.
4 CONCLUSIONS
The test results show that Flash Cache (formerly PAM II) can benefit Exchange 2010 significantly. In
summary, without adding more hard disk drives, Flash Cache can:
• Increase the number of mailboxes supported by 67%
• Increase storage use by 67%
• Double the number of achieved IOPS
This study demonstrates the benefits of Flash Cache to Exchange 2010 on a NetApp FAS3140 storage
system. The detailed results might vary with different database sizes, Flash Cache sizes, and storage
system models. At the same time, the benefits of Flash Cache to Exchange 2010 will likely carry over to
other Exchange 2010 configurations on other NetApp storage systems.
APPENDIX: FAS3140 CONFIGURATION
One FAS3140 controller and 64 1TB SATA drives were used for the tests described in this technical report.
A Flash Cache (formerly PAM II) module with 256GB cache was installed in the FAS3140. Table 3 contains
the FAS3140 configuration details for both Flash Cache enabled and disabled.
Table 3) FAS3140 configuration details.
Parameters Flash Cache Disabled Flash Cache Enabled
Data ONTAP version 7.3.2 7.3.2
HDD type SATA, 1TB, 7.2K RPM SATA, 1TB, 7.2K RPM
6 Using Flash Cache for Exchange 2010
Parameters Flash Cache Disabled Flash Cache Enabled
Number of HDDs 64 64
RAID level RAID-DP RAID-DP
Number of disks per aggregate 16 (14+2) 16 (14+2)
Number of aggregates 4 4
Number of flexible volumes per 2 for Exchange databases 3 for Exchange databases
aggregate 1 for Exchange logs 1 for Exchange logs
Number of LUNs per flexible
1 1
volume
2.08TB per LUN for database 2.08TB per LUN for database
LUN sizes
100GB per LUN for logs 100GB per LUN for logs
Number of databases per LUN 1 1
Total number of databases 8 12
Number of mailboxes per database 900 1,000
REFERENCES
[1] Exchange 2010 storage
www.microsoft.com/exchange/2010/en/my/storage.aspx
[2] Flash Cache
www.netapp.com/us/products/storage-systems/flash-cache/
[3] FAS3100 series
www.netapp.com/us/products/storage-systems/fas3100/
[4] TR-3574: “Using NetApp RAID-DP in Exchange Server 2007 Storage Designs”
http://media.netapp.com/documents/tr-3574.pdf
[5] Microsoft Exchange Server Jetstress 2010
http://technet.microsoft.com/en-us/library/ff706601(EXCHG.141).aspx
ACKNOWLEDGEMENTS
The author would like to thank Larry Freeman, Chris Lemmons, Amit Shah, and Mark Woods for helpful
discussions and suggestions, and Keith Griffin for testbed setup.
7 Using Flash Cache for Exchange 2010
NetApp provides no representations or warranties regarding the accuracy, reliability or serviceability of any
information or recommendations provided in this publication, or with respect to any results that may be
obtained by the use of the information or observance of any recommendations provided herein. The
information in this document is distributed AS IS, and the use of this information or the implementation of
any recommendations or techniques herein is a customer’s responsibility and depends on the customer’s
ability to evaluate and integrate them into the customer’s operational environment. This document and the
information contained herein may be used solely in connection with the NetApp products discussed
in this document.
© Copyright 2010 NetApp, Inc. All rights reserved. No portions of this document may be reproduced without prior written consent of
NetApp, Inc. NetApp, the NetApp logo, Go further, faster, Data ONTAP, FlexVol, RAID-DP, and Snapshot are trademarks or
registered trademarks of NetApp, Inc. in the United States and/or other countries. Microsoft is a registered trademark of Microsoft
Corporation. All other brands or products are trademarks or registered trademarks of their respective holders and should be treated
as such. TR-3867
8 Using Flash Cache for Exchange 2010


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