System load is very high because of MailScanner

[Ugo Bellavance]

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Rakesh wrote:
> BG Mahesh wrote:
> 
>>>> # As a rough guide, try 5 children per CPU. But read the notes above.
>>>> Max Children = 5
>>>>
>>>> I guess I have to change it to 10 and see how things work as we have
>>>> a dual processor
>>>>     
>>>
>>> You can try it out, it might help or not though, depending on many
>>> factors.  As other said, the message delay is the only factor that's
>>> always a good indication.
>>>
>>> Is this a dedicated MailScanner machine?
>>>
>>>   
>>
>>
>> Yes..the system is used as our mailserver. No other development work
>> etc goes on this machine. It process mail and just mail
>>
>>  
>>
> I have recently faced a similar problem especially during the sober and
> mytob outbreak, Servers were slow in processing the mails, I receive
> about 2 lac of mails  per day on individual servers and the mail hit
> rate on the servers were high than the processing rate and usually at a
> given point of time there used to be 1 K of mails waiting in the queue
> to be processed by MailScanner. Here is what I did to optimise my setup
> and thought this might help you.
> 
> Reduced the number of Max Children to 5 from 10 (Although I have dual
> Xeon and 2 gigs of RAM)
> Kept a decent batch size not too high and not too low : 20
> 
> from vmstat and iostat outputs I found tht IO was a prob for me
> so I mounted /tmp (area where SA and clamav decomposes mail ) on tmpfs.
> Many would say tht its a bad idea to put /tmp on tmpfs as chances are
> there tht it might grow up and hog up all the memory so I put a size cap
> on it using -size option in mount and did some tests on dummy machines
> to ensure tht its not spilling over the specified limit and since this
> server is just an Anti-Spam/Anti-Virus gateway it was easy for me to
> ensure tht no other apps create their dummy files in /tmp.
> 
> This has reduced the disk IO on the system and increased the processing
> to some extent. Now its usually 50 mails at a given time waiting in the
> queue to be processed by MS, while the mail hit rate remains the same.
> 
> 
> 

What OS are you running?  It is fairly common to use tmpfs for working
directory.

http://wiki.mailscanner.info/doku.php?id=maq:index&s=tmpfs#optimization_tips

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