Performance problem (high Load average) in Mail Server

[Matthew Galgoci]

> 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?

-- 
Matthew Galgoci
GIS Production Operations
Red Hat, Inc
919.754.3700 x44155