Greg Hellings wrote:
> We've been having terrible load issues with 2.0.9 and only about 300
> users.  We've got dual 3.6ghz Xeons with 1M L2 cache and 4G of ram and a
> RAID5  979G.  During our heavy load hours (9-5) the system crawls to the
> point of timing out many mail client operations.  The load averages are
> extremely high, and Mysql and Dbmail-imapd are using a ton of cpu.
> 
> Our clients are using a mix of Entourage, Mail.app, Thunderbird, and
> squirrelmail (only 5 or 10 webmail clients during our heavy load period).
> 
> Our dbmail_messageblk is about 220G right now.


What does the slow query log teach you? What kind of imap commands do
your clients typically use? In my experience, imap search can easily
cause the kind of problems you're describing.

Consider splitting the mysql server and the imap frontend server(s);
since both are cpu hungry you're likely to suffer thread trashing and/or
excessive context switching.



-- 
  ________________________________________________________________
  Paul Stevens                                      paul at nfg.nl
  NET FACILITIES GROUP                     GPG/PGP: 1024D/11F8CD31
  The Netherlands________________________________http://www.nfg.nl

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