Performance problem (high Load average) in Mail Server (fwd)

[Mahesh Shinde]

Dear Matthew,

We are using Trend micro's IMSS antivirus software and its processes consumes 
normally around 1 GB of RAM. But this software is running from last 6 months 
and we are facing problem of high load average from last one month.

What I observed recently in "top" is 2 or 3 httpd processes are using more that 
25% of CPU resources and then load average goes on increasing in the range of 
10 to 20. After restarting "httpd" service load average comes to normal.

What is causing "httpd" to suddenly consuming high CPU resources and how to 
find out where is going wrong?

Please reply,

Regards,
Mahesh Shinde
C-DAC, Pune
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On Thu, 22 Sep 2005, Matthew Galgoci wrote:

>> IBM X-345 Intel-based Server
>> DUAL Intel Xeon 2.6 GHz
>> 2.5 GB RAM
>> 3 Nos. 72 GB HDD
>> 
>> OS: Red Hat Enterprise Linux 3 AS Update 5
>> kernel: 2.4.21-32.0.1.ELsmp
>> 
>> We are regularly updating the recommended patches from Red Hat Network on
>> Mail Server and it was working fine. But from last 15 days we are facing
>> severe load problems due to which server gets busy and user experencing
>> low response/time-outs while accessing mails from their email clients.
>> 
>> We observed that the busiest process is usually kscand, and overall kscand
>> and kswapd have the highest CPU utilization times.
>> 
>> As per recent test the server perform well after initial boot, but after
>> some time only 20 MB of free memory space left out of total 2.5 GB RAM and
>> around 1 GB swap space get used out of 2 GB of swap memory. After that
>> kscand gets much busier and CPU load seems to increased wildly.
> 
> kscand is looking for pages to evict so it can page in stuff that is
> already on swap that needs to run. Basically, you don't have enough
> ram for what you are trying to do, or something is running amuck and
> consuming all of your ram - and it's not kscand.
> 
> What does a ps -fwax show when kscand is busy?
> 
>