100% CPU

chasd chasd at silveroaks.com
Mon Jul 2 16:27:11 CEST 2007


It is possible that CPU usage isn't the root cause of the system  
slowdown, just one of the symptoms. Sometimes high CPU usage can be  
the result of lots of disk I/O.
The processes don't really need the CPU, but once the system gets  
into a backlog because of a lot of disk I/O, CPU usage increases  
dramatically. Watch for processes that are in "D" status which  
indicates blocked for I/O most of the time.

Are a lot of users using the "search" feature ?

> top contents
> ************************************

<snip>

> PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
> 3081 apache 25 0 36660 12m 4044 R 13 0.6 1:11.59 httpd
> 3095 apache 25 0 36692 12m 4388 R 13 0.6 1:10.78 httpd
> 3897 apache 25 0 36716 12m 4360 R 13 0.6 1:15.59 httpd
> 3963 apache 25 0 36640 12m 4152 R 13 0.6 1:07.89 httpd
> 3972 apache 25 0 36708 12m 4060 R 13 0.6 1:11.78 httpd.

All apache processes, not imap processes.
IMHO, PHP is processing a lot of stuff that it got from the imap or  
db connections.
All are in "R" or running status, but 25 seems an odd priority to me,  
my apache processes run around 15 or 16 most of the time.


Charles Dostale
System Admin - Silver Oaks Communications
http://www.silveroaks.com/
824 17th Street, Moline  IL  61265





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