HP LeftHand P4000 - SAN Solutions Application Notes page 9

Microsoft Exchange Jetstress
The Jetstress tool allows administrators to verify the performance and
stability of the disk subsystem before putting their Exchange server into a
production environment. It reports back to the administrator with an html
document that contains results and a PASS or FAIL for the overall test. A
PASS or FAIL is strictly based on specific test results not exceeding Microsoft
specified limits. Disk Latency is the primary metric used by Jetstress for
PASS / FAIL criteria. The values to pass are the log avg. disk sec/write,
database page fault stalls, and database avg. disk sec/read. Log average
latency should be below 10ms, database page fault stalls should always be 0,
and database average read latency should be less than 20ms. LeftHand
Networks uses an automated command line version of Jetstress that will
increase threads until the test no longer passes and records the IOPS of the
last passing run. The highest IOPS achieved while still passing is the value
reported in this paper.
Best Practice – Keep the email database files and log files on
separate volumes.
File Copy Using Robust File Copy
The file copy test is a straight-forward Windows file copy. Using robocopy.exe a
file copy of one hundred 100MB files is done from direct attached storage
(DAS) in the server to a volume on the SAN. For this test a simple
measurement of megabytes per second is taken. Robocopy (Robust File Copy)
is included in the Windows resource kit. While individual file copy speeds are
limited by the nature of low queue depth disk operations, the architecture of a
LeftHand Networks SAN solution is capable of handling multiple file copy
jobs simultaneously without degrading performance. This is represented by
the "Concurrent Jobs" set of data.
Best Practice - When copying from DAS to the iSCSI SAN remember the file
copy cannot go any faster than the DAS disk. Make sure the disk that the
source files are on is the fastest disk available to you otherwise it might be
limiting the file copy speed. Running multiple file copies at a time will
increase the aggregate performance.
IOmeter
IOmeter is an I/O subsystem measurement and characterization tool. IOmeter
is a good tool for simulating loads of different I/O sizes to demonstrate a
system's IOPS and throughput capabilities. These configurations are designed
to show typical speeds as opposed to the maximum values.
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