Re: [Exim] Exim and SMP

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Author: Nigel Metheringham
Date:  
To: K.J.Collins
CC: exim-users
Subject: Re: [Exim] Exim and SMP
The standard answer....
    it depends


Where are the bottlenecks in your system?
Do you deliver mainly to disk, is mail just transiting through, do you
do a lot of lookups etc...

Typically a mail system hits disk limitations first - mainly on the
queue directory, however the main maildrop directory may also be a
bottleneck if on the same machine.

Ways of fixing this are to spread load over more and faster disks -
Linux RAID is pretty good for this, or a hardware RAID system.

There are tools around to measure this sort of thing - there is a
vmstat now as part of linux.

More CPU is unlikely to help much unless you have a particularly CPU
bound system.

Other things that may help:-
- disk queue layout - split_queue
- fs used on disks - maybe look at reiserfs
- putting the queue onto a fast disk system
- raid 0 or 5

    Nigel.
-- 
[ Nigel Metheringham                  Nigel.Metheringham@??? ]
[ Phone: +44 1423 850000                         Fax +44 1423 858866 ]