slow populating a mailbox

[Kjetil Torgrim Homme]

On Sun, 2006-09-24 at 23:17 -0700, Ross Boylan wrote:
> I've been using the UW-IMAP mailutil to copy messages from my regular
> Unix mailboxes (for mutt) to IMAP.  The messages are all going to a
> single folder for a single user.
> 
> My impression is that this is rather slow, about 20 minutes for 100MG
> worth of messages.  There is virtually no CPU use while this happens.

number of messages is much more important than the size of them.

we've recently relocated a bunch of mailboxes using imapsync, we got a
speed of about 300 KiB/s for our users.  users which had mostly large
files with attachments went faster, traditional Unix users went slower,
perhaps a factor of two either way.

> The source traditional mailbox and destination IMAP server are on the
> same machine, using the same hard disk (no, it's not a "real" server).

that's not improving matters, of course.

> Second, where should I look to diagnose or solve this problem?

you could try oprofile to get systemwide performance numbers.

> This is Debian GNU/Linux system with a SATA disk, using EVMS volume
> management and Reiser FS.  2.6 kernel.  Pentium 4 CPU.  I'm using the
> Debian packaging of Cyrus 2.2, and have generally not done a lot of
> tuning/tweaking at any level (kernel, file system, Cyrus).

I have no idea how to tweak ReiserFS (I don't want to lose my data
again, so I stay away from it).  with ext3 I'd suggest trying async
mount, just to see the impact.  if it helps, using a dedicated disk for
the journal would be one way of improving the I/O wait.

-- 
Kjetil T.