Performance problem (high Load average) in Mail Server

[John Rumpelein]

What's eating all the RAM?

There's a whitepaper on converting to dovecot from uw-imapd (is RHEL3
uw-imapd based?) which describes performance issues like this.


On 9/22/05, Mahesh Shinde <maheshs at cdac.in> wrote:
>
> 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
>
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