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Old 02-02-2011, 12:59 PM   #1
copperkin
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Registered: Feb 2011
Posts: 2

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Courier IMAPD taking lots of server CPU


Hi All,

I am having weird issues with courier IMAPD, the load goes like crazy at times and users mail client just hangs! The server is having 4 GB RAM Dual Core and around 700 users connected to 143 (via netstat) and I see around same amount of imapd's in process list. Mailbox stays in SAN (fiber).

load is high: 105.52, 173.12, 113.05

iostat.txt

Linux 2.6.9-34.ELsmp 02/02/2011

avg-cpu: %user %nice %sys %iowait %idle
8.93 0.02 1.58 8.06 81.40

Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
sda 8.63 15.86 43.92 1202012571 3329161998
sda1 0.00 0.00 0.00 13289 110
sda2 18.12 42.28 27.61 3204466899 2092669600
sda3 3.04 0.53 24.07 39921778 1824793688
sda5 0.67 0.80 5.15 60413011 390318448
sda6 5.03 0.46 40.23 34585395 3049198512
sda7 3.61 4.53 27.35 343649222 2073400840
sda8 2.30 22.46 11.77 1702359204 892485712
sda9 0.00 0.00 0.00 33121 25296
sda10 2.66 1.47 21.06 111531036 1596103168
sdb 26.18 29.01 11.65 2199267099 883116512
sdb1 15.76 29.01 11.64 2198670915 882460488



vmstat.txt

procs -----------memory---------- ---swap-- -----io---- --system-- ----cpu----
r b swpd free buff cache si so bi bo in cs us sy id wa
0 51 160 2061772 560636 737284 0 0 0 0 0 0 9 2 81 8

Any help is much appreciated..

Thanks,
Kin
 
Old 02-16-2011, 07:48 PM   #2
thegeek
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Registered: Oct 2009
Location: Amsterdam
Distribution: CentOS,Fedora,Puppy
Posts: 62

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Hello,

Perhaps you should set up some debug logging in your courier-imapd server, and get more information on what is happening.

Here is a guide: http://winunixmac.com/tips-and-trick...-debug-logging

Its worth mentioning that even FC disks on a SAN can become overloaded with too much I/O.
From the IOwait reading in the output you give, its highly likely.

HTH

Last edited by thegeek; 02-16-2011 at 07:55 PM.
 
  


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