[SunHELP] qmail performance on ufs file system

Bob Ruddy sunhelp at sunhelp.org
Tue Jun 19 17:45:53 CDT 2001


Ok on my first day at the new job they have me help trouble shoot a brand
new qmail install....

Quick look at iostat while testing the system shows the bottle neck is
/var/qmail/queue which is where each message gets written as a seperate file
as soon as it is received. To test my therory i mounted that onto tmpfs so
esentially that file system is in memory. I was correct. That was our bottle
neck. As throughput went way up and iowait was almost zero.

The setup these boxes have is solaris7. Running on a 220 with 2 gigs of ram
and 2 450mhz procs. The two internal disks are mirrored. The queue is on a
mirrored slice. 

So see how much mirroring cost i unmirrored the /var/qmail/queue file
system. Instead of my throughput being 400 messages for five minutes it is
now approx 600. So that is better but not optimal yet.

The three questions I have for this group are this. What I need to optimize
is reading and writing small files ~ 1k fast.

1) what will vxfs buy me?
2) how much will the tuning of ufs get me?
3) where is a good resource for tuning ufs?

Thanks for you help,
Bob




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