MailScanner dying occasionally?

Julian Field mailscanner at
Sun Nov 24 17:36:30 GMT 2002

2 or 3 people here have been having a few problems recently with
MailScanner occasionally dying, particularly in or

This has turned out to be a resource limit problem, where you have a mail
server that
    a) is heavily loaded,
    b) only actually scans a small fraction of the mail going through it,
    c) has a relatively low limit for the number of open files at once
(e.g. 1024).

The default value for the
        Max Unscanned Messages Per Scan
parameter has always been supplied at 500, causing these systems to run out
of open files. (MailScanner needs 2 open files per message in a batch)

The solution is very simple, just set
        Max Unscanned Messages Per Scan = 100
and you will be fine. There should be no noticeable loss in performance or

I have adjusted the default value in the distribution to match.

Julian Field                Teaching Systems Manager
jkf at         Dept. of Electronics & Computer Science
Tel. 023 8059 2817          University of Southampton
                             Southampton SO17 1BJ

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