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 |
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 |
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