From: Ralph R. Rye (RyeR@SCHNEIDER.COM)
Date: Tue Mar 23 2004 - 10:27:19 EST
We have altered our queue depth from the default of 8, but we are using
metavolumes. The queue depth we typically set with metavolumes is 8 * the
number of meta members, which is typically a 4 or 8 member metavolume.
We definitely have seen a difference in performance on metavolumes. The
other item you may want to look at is the "queue depth" of the HBA
[attribute = num_cmd_elems]. By default this is 200, so depending on the
number of luns down the path you may be restricting the performance.
Ralph
Raj Atwal
<atwalrs@YAHOO.CO To: aix-l@Princeton.EDU
M> cc:
Sent by: IBM AIX Fax to:
Discussion List Subject: Queue Depth for EMC
<aix-l@Princeton.
EDU>
03/23/2004 09:05
AM
Please respond to
IBM AIX
Discussion List
I would be interested to know if anybody who is running an EMC disk
subsystem and has altered the queue_depth setting on the hdiskpower
devices?
If so, how did you determine what value to use from the default 8, and how
much of a benefit did you gain in your opinion?
TIA
Raj Atwal
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