Cyrus IMAP Presentation

[adam at morrison-ind.com]

>>>(Slide 16)
>>>- "-n 5" is probably low for a reasonably high traffic site.
>>I've got about 200 users,  if there should be more threads will
>>authentication fail or just be really slow?
>Authentication will start to fail (atleast when using unix domain
>sockets), because the saslauthd listen queue will fill up.  I don't
>believe the doors IPC mechanism has this problem, since it allocates
>threads dynamicly (though you need to be on Solaris).
>Though, with only 200 users I doubt you have much to worry about unless
>they all decide to log in at once, in which case you'll crush the machine
>just fork()ing that much.  A good guess for the number of threads you want
>is about 1.5 x the average number of connections you see in a second,
>which errs slightly on the high side.

Ok,  I'll toss the 1.5 rule on the new performance slide.

On another performance note; is it safe to do noatime on the mail filesystem
and/or configuration filesystem?  Or does cyrus make use of these attributes?