Mail server backlogging - seems like a Bayes problem

[Ron E.]

On Thu, 21 Oct 2004, Matt Kettler wrote:

> At 02:25 PM 10/21/2004, Ron E. wrote:
> >Dear All,
> >
> >         Hopefully someone has an idea for me - I have a server that
> >normally handles it's traffic load but this morning has started
> >backlogging - I ran MailScanner in debug mode and the only real point of
> >long delay I saw coming up repeatedly is:
> >
> >debug: bayes: Can't use estimation method for expiry, something fishy,
> >calculating optimal atime delta (first pass)
> >debug: bayes: expiry max exponent: 9
> >
> >The above messages I have only sometimes seen before when doing a bayes
> >database rebuild, but not always.
> >
> >Anyone have any ideas why this is happening repeatedly within one
> >MailScanner batch and how I can alleviate it?
>
> Any chance MS is timing SA out and killing it repeatedly? (this can happen
> if SA does expiry and it takes too long for MailScanner's rather absurdly
> short default timeout).
>
> If this is the case, Re-quoting myself from a post to the SA user's list:
> --------------------------------
> In the short term, you can help by running a sa-learn --force-expire on
> your bayes DB.
>
> In the longer term, here's some suggestions I use on my own MailScanner
> server: (I use all of these together)
>
> 1) Increase the spamassassin timeout in MailScanner.conf. Bring it to 60
> seconds at least, I have mine set to 120.
>
> 2) Set the "Rebuild Bayes Every" parameter in MailScanner.conf. 86400
> seconds is a good start. This makes MailScanner invoke SA's bayes
> housekeeping directly, rather than during a scan of a message.
>
> 3) in /etc/mail/spamassassin/local.cf set: bayes_auto_expire 0. This will
> keep SA from trying to run bayes expires (long and slow) during message
> handling, but relies on #2 above to allow expiry to occur.
>
> 4) I also have a sa-learn --force-expire running as a daily cronjob. I have
> tested the setup without this measure, and #2 is sufficient to cause expiry
> to occur. Really this is just a fail-safe to allow expiry to occur even if
> MailScanner's calls fail to run it properly for some reason.
>
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Hi Matt -

        Thanks very much - I think that is very likely what's happening
and actually it makes sense as that is probably the cause of some other
timeouts I've had trouble tracking down. As it happens after I posted the
above, I thought that I should probably do a rebuild manually which I did
in addition to the suggestions you make above. Anyway, looks good so far
and no more backlog.

Regards,

Ron

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