Re: SquirrelMail slow, VERY slow

[Will Yardley <taroon veggiechinese net>]

On Wed, May 25, 2005 at 02:24:28PM -0400, Doug Stewart wrote:

> I've been tasked with setting up a SquirrelMail IMAP install for our 
> intranet.  My users have been seeing *extremely* lengthy login times, 
> sometimes on the order of 45 seconds - 1.5 minutes.  (The webserver 
> running SM and the IMAP server are two separate boxes). Also, several 
> users are encountering the following issue when trying to log in:
> 
> ERROR:
> ERROR : Connection dropped by imap-server.
> Query: EXAMINE "INBOX"

Do your mail logs say anything? Are you running imapd from inetd /
xinetd? Depending on the number of users, you may want to make sure that
enough imapds can run to handle the number of users you're supporting,
etc. You should also make sure that you've set the UW-specific options
on the IMAP server. If you have server-side threading enabled, you may
want to disable it (or vice-versa if it's disabled).

Do you see similar delays with a different IMAP client? How about if you
use Pine from the Squirrelmail machine? What's the typical inbox size
for your users? Obviously if the delay is consistent across various IMAP
clients, it's much more likely a general IMAP problem.
 
A DNS resolution problem (as mentioned by others) does seem like a
likely scenario, so even if you're pretty sure everything is kosher
there, you might want to doublecheck.

If you do (from the Squirrelmail client machine):
% telnet localhost 143

and then:
a1 login username password

you should see something like:
a1 OK [CAPABILITY IMAP4REV1 IDLE NAMESPACE MAILBOX-REFERRALS BINARY
UNSELECT SCAN SORT THREAD=REFERENCES THREAD=ORDEREDSUBJECT MULTIAPPEND]
User [username ] authenticated

then do:
a2 select INBOX

and see if it hangs before returning something like:
* 169 EXISTS
* 0 RECENT
* OK [UIDVALIDITY 1114126468] UID validity status
* OK [UIDNEXT 171] Predicted next UID
* FLAGS (\Answered \Flagged \Deleted \Draft \Seen)
* OK [PERMANENTFLAGS (\* \Answered \Flagged \Deleted \Draft \Seen)]
* Permanent flags
a2 OK [READ-WRITE] SELECT completed

On Wed, May 25, 2005 at 03:49:26PM -0400, Doug Stewart wrote:

> Forgot to mention that part: the IMAP server is indeed wu-imapd, but
> it's running on a Solaris 8 box

What version of wu-imapd? Is it possible to upgrade if it's not the
newest version? There are also some compile-time options which you may
want to look into. Are the mail files mounted via NFS anywhere, or are
they all on a local filesystem?

If all access is via IMAP, you might consider using UW's "mbx" format -
this would require some conversion, but might be a little higher
performance. You can use the "mailutil" program to convert between
formats.

I've used Squirrelmail (not using the Red Hat version specifically, and
not on Red Hat) for an installation a really large number of users, and
I've never seen performance problems other than those due to the IMAP
server itself and / or DNS resolution.

w