We run a mail service with some hundreds of domains and thousands of
users. Xeon 2 CPU server hosting the imap, pop, webmail, db and all
trimmings (sepparate servers scanning for spam/viri)
The server was io saturated and performing poorly, especially for
large webmail users. A constant queue of hundreds of ops per second
were taking too many miliseconds each (gstat.) Load average often
spiked over 15! We planned to add a second backend imap/pop machine
but first migrated to dovecot (from courier.)
Like a miracle, the load average stays below 1 now, nor do the disks
saturate! All's well and webmail performs snappily even during peak
usage!
Granted we also upgraded freebsd which supposedly has made leaps to
better schedule tasks across multiple processors, but this is not a
many core machine - just 2.
We almost don't need to scale up our architecture, tho will, thanks so
very much for this wonderful software Timo!
