Debugging and resolving high loadavg when running MailScanner

Ugo Bellavance ugob at CAMO-ROUTE.COM
Wed Feb 16 19:49:24 GMT 2005

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Richard Curtis wrote:
> Hi All,
>   I have been running MailScanner (Version 4.35.11) for some time, but
> over the last 2 -3 weeks, my loadavg has gone from ~0.10-0.20 to as high
> as 4.  This may not seem high to some, but as I have other services on
> this box I want to try to reduce the load.
> The box runs httpd, sendmail/MailScanner with clamav, radius and pop.
> There are multiple hosted domains on the server.
> The box is a dual AMD Athlon MP 1200 with 512MB RAM.
> All mail is scanned through MailScanner for virus's, but only a small
> number of the domains (low traffic ones) have SpamAssassin enabled in
> MailScanners configs.
> I have to admit that I am a bit confused by some of the MailScanner
> config options - for example, the effects of "Deliver In Background =
> yes" and "Delivery Method = batch".
> By setting the delivery method to queue, what kind of impact on delivery
> time can I expect ?  Will this have a significant effect of lowering the
> load ?
> One other question, I note from looking through the logs, I see entries
> like:
> Feb 16 11:25:32 lancelot MailScanner[7544]: New Batch: Scanning 1
> messages, 1720 bytes
> Feb 16 11:25:32 lancelot MailScanner[7544]: MCP Checks completed at 1720
> bytes per second
> Feb 16 11:25:32 lancelot MailScanner[7544]: Spam Checks completed at
> 1720 bytes per second
> Now what confuses me here is that I have MCP checks and Spam checks set
> to off for this mail domain - so why are the checks happening ?
> Any suggestions on performance tuning of MailScanner, or possible
> sendmail config tweaks would be greatly appreciated.

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