[PLUG] Email server performance

Robert Anderson riznob at gmail.com
Fri Apr 15 17:59:31 UTC 2005


Hi All, I am having some email server performance issues. Users report
that the performance is horribly slow. I have witnessed this poor
performance. It is only horribly slow during business hours, when
everyone is using it. There are about 180 users who mostly use imap to
access email. The machine seems to have plenty of processing power, 4
Zeons and 4 gigs of ram. I wrote a script to collect some data every
hour. The script collects output from top, vmstat and ps. I noticed
from the vmstat output that there seems to be a lot of disk io, but it
does not appear to be due to swapping. Here is some output from
vmstat:

procs                      memory      swap          io     system      cpu
r  b  w   swpd   free   buff  cache   si   so    bi    bo   in    cs us sy id
 0  4  1  57628  14908 218568 1494248    0    0   768  2812  703    52  0  1 99
 0  4  1  57628  14968 218568 1494248    0    0   768  1824  796   103  1  1 97
 0  4  5  57628  15156 218572 1493808    0    0  1536  1800  653   134  0  1 99
 0  3  1  57628  17176 218572 1499476    0    0 10880   452  438   482  1  3 96

Any ideas of how I could address the performance problems? Should I
switch the users to pop3? Put a cap on mailbox size? Any help is
appreciated.

-- 
Rob Anderson
riznob at gmail.com



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