Cyrus folder list takes a very long time to return

[Gavin Kelman]

We're running Cyrus IMAP v2.1.14, and have been for quite some time.
We've had squirrelmail setup for a few months and use it occasionally
and it lists folders just fine, nice and quick.

Last week I setup Horde and IMP and it worked fine for a few days, then
yesterday it suddenly takes 15-30 seconds to bring up the folder list.
After plenty of experimentation, I decided to telnet directly to the
Cyrus IMAP server and do the following:

[root at waterhouse kelman]# telnet waterhouse 143
Trying 172.18.6.22...
Connected to waterhouse.lionbio.co.uk (172.18.6.22).
Escape character is '^]'.
* OK waterhouse Cyrus IMAP4 v2.1.14 server ready
. login username password
. OK User logged in
. list "" *

At this point, I have to wait a good long 15-30 seconds for the folder
list to come back.

The Cyrus server is a Dual P4 2.4Ghz with 1GB RAM and hardware RAID
SCSI disks for the storage. We have upto about 40 users logging
in, and the load on the machine never goes higher than 0.02. Most
of the time it's 0.00. Watching top while the . list command is
running, no imapd processes appear to be working hard.

I've run squatter against my mailbox folders and it's indexed them all.
It seemed to be a little faster afterwards, but still taking a VERY long
time.

So the questions are:

1) Why does '. list "" *' take so long to return a list of folders?
There are only 30 folders in my mailbox.

2) Squirrelmail, Outlook and Thunderbird seem to pick up the list
of folder instantly, with no delay. How come? Caching may certainly
be an issue, but I've tried to eliminate this.

3) Am I (and therefore Horde/IMP/PHP/C-client libs) using the right
command to list the mailbox folders? Is there some cyrus specific
command to list them quickly?

Cheers,
Gavin.
-- 
Gavin Kelman
UNIX Administrator
LION Bioscience Ltd.
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