Just thought I'd share this information with you.
CentOS 4.3's latest Kernel (as far as I'm aware - pre 2.6.9-37) is very buggy when it comes to RAM usage and swap memory usage. It swaps needlessly and doesn't utilise all of the RAM before using the swap file. Because of this you may get quite high IO/waits. Stuff like updatedb running or cpbackup will utterly destroy your box - it happened to me.
* USE AT YOUR OWN RISK - THIS IS A BETA KERNEL *
I've been testing this Kernel for the last couple of weeks and so far so good, haven't had a single problem with it at all and the performance increase has been VERY worthwhile.
To fix this bad memory management 'bug', try this beta kernel:
http://people.redhat.com/~jbaron/rhel4/RPMS.kernel/
On a high load 4GB RAM box we've never even used the swap file since applying it - MUCH better performance all round.
Download the relevant RPM for your setup, then:
rpm -Uvh <filename>
Reboot, job done.
CentOS 4.3's latest Kernel (as far as I'm aware - pre 2.6.9-37) is very buggy when it comes to RAM usage and swap memory usage. It swaps needlessly and doesn't utilise all of the RAM before using the swap file. Because of this you may get quite high IO/waits. Stuff like updatedb running or cpbackup will utterly destroy your box - it happened to me.
* USE AT YOUR OWN RISK - THIS IS A BETA KERNEL *
I've been testing this Kernel for the last couple of weeks and so far so good, haven't had a single problem with it at all and the performance increase has been VERY worthwhile.
To fix this bad memory management 'bug', try this beta kernel:
http://people.redhat.com/~jbaron/rhel4/RPMS.kernel/
On a high load 4GB RAM box we've never even used the swap file since applying it - MUCH better performance all round.
Download the relevant RPM for your setup, then:
rpm -Uvh <filename>
Reboot, job done.