I thought I would follow up on this question I had about a month
ago.
Recap: Sun host 300GB database, on iSCSI, performing very poorly.
Initial indication were that iSCSI was causing very slow reads.
I suggested that the remote site open up a case with TSM support
too diagnose. Waited, waited, asked, waited, waited....
Just found out that instead of troubleshooting the issue, they
moved the DB volumes from the iSCSI devices to some other locally
attached storage and there performance is once again acceptable.
Asked for details about the new storage and it's layout and
connections, etc, but getting no reply.
So.... About all I can do is extrapolate a generalization that,
"For some unknown reason, their configuration of iSCSI on this Solaris
host was insufficient to keep up with a busy TSM server." Does that mean
that iSCSI is not a match for TSM in general? I don't have enough
information, but I would suggest that great care be taken in designing
and implementing a robust environment if you were to attempt iSCSI on a
TSM (or other OLTP-like) server."
Sorry, I got nothing more than just generalizations from one
data point.
Ben
-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of
Kelly Lipp
Sent: Monday, May 14, 2007 1:38 PM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Re: Poor TSM server performance on Sun.
I'll be very interested in the outcome of this one! I guess I'm not
surprised that it's slow. I will be surprised if it ever works well.
But that's just me!
Kelly J. Lipp
VP Manufacturing & CTO
STORServer, Inc.
485-B Elkton Drive
Colorado Springs, CO 80907
719-266-8777
lipp AT storserver DOT com
-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of
Ben Bullock
Sent: Monday, May 14, 2007 12:01 PM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: [ADSM-L] Poor TSM server performance on Sun.
Folks,
I have a TSM server running on a Sun host running SOL 9, 16GB
RAM, and TSM 5.3.4
The problem is very poor performance, expire inventory goes
extremely slowly, even archives of 20GB files going to disk or tape are
very slow. Just slow slow slow.
But all of the typical things I look at (the bufpool, log wait,
accounting logs, iostat, etc) look ok. No MediaW or IdleW, everything
seems to be in a "Run" state, but going slowly.
All the storage (DB, LOG and STG) is on ISCSI out to an EMC
Clariion. The disk ~seems~ to be OK, but running a TSM DB and LOG on
iSCSI is a new configuration for us. At the OS side, it doesn't think it
is waiting for I/O (with an 'iostat' command), but I'm not sure if the
iSCSI protocol may be hiding the i/o waits from the OS, Any comments,
good or bad, from someone running TSM DB & LOG on iSCSI?
I ran a little instrumentation on the host for less than a
minute and the final output looks like this:
TOTAL SERVER SUMMARY
Operation Count Tottime Avgtime Maxtime InstTput RealTput
Total KB
------------------------------------------------------------------------
----
Disk Read 435 58.100 0.134 0.963 281.2 1068.6
16340
Disk Write 97 14.632 0.151 0.504 1128.7 1080.2
16516
Tape Read 1 0.039 0.039 0.039
Tape Write 129 28.167 0.218 0.547 1154.2 2126.3
32512
Data Copy 127 0.080 0.001 0.000
Network Recv 2094 107.587 0.051 5.923 152.3 1071.5
16384
Network Send 198 0.021 0.000 0.000 39647.0 54.9
840
Acquire Latch 91 44.514 0.489 2.019
Acquire XLatch 359 148.127 0.413 4.327
Thread Wait 2192 106.077 0.048 5.958
Instrumentation output complete.
I'm going to open a performance case with Tivoli, but it looks like
most of the time is spent in "Acquire Xlatch", anybody have an idea what
that is?
Any wild guesses are welcome.
Thanks
Ben
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