From: Johan Hartzenberg (jhartzen@csc.com)
Date: Thu Oct 12 2006 - 09:09:10 EDT
I have recently (In the past several months actually) been frustrated that
the %w column, as well as the wsvc_t column, always shows zero values when
viewing the extended disk statistics.
This ia happening on Solaris 8, 9 and 10 with varying patch levels, and
the same is true for both server internal disk, Fibre-channel SAN fabric
connected disk and Fibre-channel loop-mood connected disk, in fact, for
all the servers that I have available. However I am sure that in the past
this was not always like that, and that %w used to give meaningfull
values.
Even running a little script to kick of multiple dd commands to read from
a disk and write it back to a file on the same disk in parrallel will
quickly cause the IO to become congested, but nothing shows up in the
io-wait statistics columns.
Does anybody else have a similar experience? Does anybody have a
solution? I have an open case with Sun on this but I thought I'd ask on
this forum as well because of the high quality of responses this list
normally generates. I need this information to try and resolve some
urgent performance problems with servers that use used as media servers in
a disk-based backup environment, so the disk IO statistics are very
important and the problem is hurting us at present.
Thanx,
_Johan
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