problem on a MX sendmail machine

[Mel Flynn]

On Monday 01 June 2009 11:33:59 RJ45 wrote:
> hello I have a FreeBSD machine
>
> FreeBSD infngw.infn.it 7.0-RELEASE-p2 FreeBSD
>
> being a MX record with high loads.
> I often ahve this message on logs right before the machien locks up.
> any hints ?
> thank you
>
> swap_pager: indefinite wait buffer: bufobj: 0, blkno: 482607, size: 61440

a) Check disk connectivity and health
b) Don't let your mailserver swap:
   - add memory and/or
   - divide load over multiple machine
c) Limit disk io if you cannot stop occasional swaps:
   - mailstore on different physical disk then queue, no swap on this disk
   - memory disk for logs
   - switch to Maildir if using mbox

Mailservers are particularly bad for swapping as every new request will 100% 
result in one disk write (the logfile) and possible more (header file, queue 
body).
-- 
Mel