[imp] IMP authentication and email access very slow

[Gavin Kelman]

I've been running Horde 3.0.2 and IMP-h3-4.0.1 for about a week now,
with Apache 1.3.33 with mod_ssl against OpenSSL 0.9.7e. The IMAP
server is Cyrus, running on another machine. IMP worked fine for a
few days, everything nice and fast, no complaints.

Then yesterday I noticed it was incredibly slow logging in and accessing 
or composing email. The rest of Horde is running fine, options and
administrator pages load very quickly, just as before.

The apache logs show nothing at all wrong, the machine is running at a 
load of 0.01, and there's plenty of RAM free. The box is a dual P4
2.4Ghz with 2GB RAM and it's running RedHat AS 3.0 Update 3 and MySQL
4.0.22 and nothing else, the box is dedicated to running Horde and IMP.

I've reviewed the Performance notes on the Horde website, but feel
that there's nothing relevant to this problem. There's only myself
using IMP, and our Cyrus IMAP mail server is also ticking along
at 0.01 load at "peak".

PHP isn't logging any errors to the apache log files, that is, there
are no errors. If I break the horde configuration, I get PHP errors
in the logs, as expected.

So, the question is, what can I do to investigate the problem? As
far as I can tell, it's just slow all of a sudden. I've restarted
Apache and MySQL, with no visible change.

Cheers,
Gavin.

-- 
Gavin Kelman
UNIX Administrator
LION Bioscience Ltd.