Question on reducing load on MailScanner machine

Christopher Fisk cfisk at
Thu Jun 25 20:16:45 IST 2009

>  on 6-25-2009 11:37 AM Christopher Fisk spake the
>  following:
>  > I saw a similar post in the archives recently, but the
>  discussion didn't go very far.
>  > 
>  >
>  -June/092018.html
>  > 
>  > I'd like to expand the question a bit.
>  > 
>  > Lets assume I have a single server handling MailScanner
>  (& SA & ClamAV) and the postfix/courier servers.
>  > 
>  > The MailScanner queue is reaching 300+ at times, giving
>  a short delay between the server receiving the message
>  and MailScanner scanning it.
>  > 
>  > If I were to NFS/SMB mount both the MailScanner install
>  directory and the hold queue directory from another
>  machine and startup another MailScanner process, will I
>  run into issues where both MailScanners are trying to
>  scan the same messages and cause problems?  Or would
>  MailScanner be smart enough to know that another
>  MailScanner process is scanning a given message?
>  > 
>  > 
>  > This is on Linux 2.6 and ext3.  Filesystems and kernel
>  versions can be changed as needed.
>  > 
>  > I have a few extra servers I can quickly put in place
>  and would rather do that than purchasing an entire new
>  server for this.
>  > 
>  > The MailScanner book doesn't have any information on
>  this type of configuration unfortunately.
>  > 
>  > 
>  > Thanks!
>  > 
>  > 
>  > Christopher Fisk
>  > 
>  I doubt if postfix would like this.

Actually, I see postfix as handling this better than MailScanner.  Postfix just delivers the incoming messages using a header check into a hold queue, one message per file in the queue.

MailScanner scans messages in that queue and delivers it to the postfix incoming queue.

What I'm more afraid of (And what Julian says would cause problems) is the MailScanner on server A and the MailScanner on server B both picking up the same message from the hold queue, scanning it, then delivering to the deliver queue and the recipiant receiving multiple copies of the same message.

Christopher Fisk

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