[Dovecot] Just some user input

[Brandon Lamb]

Hi Timo,

You may remember some of my mails, I was having unusual high load
issues using pop3 with dovecot over nfs, and unusual being the load on
anywhere from 1 to 4 servers would run at 2 to 4 for a week then all
of a sudden would spike to 60 and higher (saw 150 once).

I have been banging my head on the wall for the last 1.5 to 2 months
since switching from courier to dovecot, the imap has worked great but
the pop3 was a problem out the door.

Anyway, I finally tried loading dovecot directly on our raid, all
loads across the board dropped to the floor. The single P4 3ghz purrs
along at an easy 0.30 load where the 1 to 4 quad core boxes with brand
new hardware were loading up to 60 when using nfs.

So, my experience has been that maildir, nfs and dovecot as the pop3
server was unusable. I wasnt really sure this whole time, it seemed
odd that a single P4 box using nfs and courier pop3 could handle the
entire system load but dovecot with the same and more quad cores fell
over was weird.

Anyway, this is totally not meant as a bashing or anything, just
information. Im not a C programmer so I really cant offer anything but
my input/observations. Maybe the pop3 part of dovecot isnt really
given much love or people are mostly just interested in the imap
server? Or maybe most people dont use nfs? Totally just assumptions
here.

A definite positive here though, after moving dovecot directly to the
raid server, wow, our mail TOTALLY hauls ass now. Two of our managers
both noticed the huge speed increase. One of them uses pop3 and leave
messages on server and has almost 4,000 messages in the inbox on the
server, his webmail now loads literally instantly, i click login and
count 1 second. That is amazingly fast.

I dont have any hard numbers, but before our upgrades his "feeling"
was that he seems to remember it taking up to 30 seconds for webmail
to load his mailbox. that is an incredible difference. Our webmail
uses imap by the way, so this is probably a combination of moving from
nfs and switching from courier to dovecot.

Ok thanks for your great hard work and sorry for the novel size post.