Performance problem (high Load average) in Mail Server

[Mahesh Shinde]

We have a Mail Server with following Hardware/Software configuration.

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.

Please provide us solution to this critical problem at the earliest.

Regards,
Mahesh Shinde
C-DAC, Pune