Veritas-bu

[Veritas-bu] T2000 Tuning Suggestions

2007-06-18 17:06:20
Subject: [Veritas-bu] T2000 Tuning Suggestions
From: "Green, Steven" <steven.green AT teldta DOT com>
To: <veritas-bu AT mailman.eng.auburn DOT edu>
Date: Mon, 18 Jun 2007 15:31:57 -0500
We've recently acquired a Sun T2000 for use as a media manager to
replace an old and dying Ultra450. The server configuration is as
follows:

        Solaris 10
        8-core, 16Gb
        Emulex LP11000 (dual-port) for disk-SAN connectivity (2Gb/s port
speeds) to CLARiiON CX380, using Leadville driver
      Qlogic  QLE2462 for tape-SAN connectivity (LTO2's via 2Gb/s MD4500
switch)
        Netbackup 6.0/MP4 - Number_buffers=128 (probably overkill),
size_buffers=262144

I'm just beginning to do testing on this hardware, but am frustrated at
what I'm experiencing thus far. I import/mount a slug of file systems
from a set of clone volumes of one of our production hosts, then run a
tape backup to two tape drives (6 concurrent streams, MPX=3/drive) and
measure the result. This is a local backup and does not involve network
traffic. What I get is ~50Mb/s for each of the tape drives - a total of
100Mb/s overall. Not bad (better than the Ultra450, to be sure), but ...

Regardless of how I increase/decrease the number of drives, MPX level,
etc within Netbackup I am 'stuck' at the max of 100Mb/s - I cannot get
any more regardless of what I do. I've run manual bpbkar's (piping
output to /dev/null) and can prove that I can read from disk at a
minimum of 180Mb/s (90% utilization on each 2G disk-SAN connection), so
reading does not seem to be the bottleneck. When I direct the output to
tape my switch tells me that I'm pushing the 2Gb connection from the
media server to the tape-SAN switch at approximately 50% utilization
(and likewise from switch to actual tape target). 

If I run two MPX'd backup streams to a single tape drive (MPX=2/drive) I
can push the drive to 100Mb/s as reported by 'iostat' on the media
server. If I then split the streams and send each to its own tape drive
(MPX=1/drive) the per-drive throughput drops to 50Mb/s. If I add a 3rd
tape drive and steam (3 streams, each to its own drive) the per-drive
throughput drops to ~33Mb/s. It seems like something is throttling the
server to a max of 100Mb/s - but I cannot grasp what it is. Any thoughts
from some of you more experienced admins would be of immense help.

Thanks in advance....

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#!/usr/local/man/steve green :: Storage Administration
Telephone & Data Systems, Inc.
608.664.8210 (immobile) :: 608.219.2106 (mobile)
 
What can be asserted without evidence may be dismissed without evidence.

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