slow populating a mailbox

Ross Boylan ross at
Thu Sep 28 12:56:40 EDT 2006

On Mon, Sep 25, 2006 at 12:04:20PM +0200, Kjetil Torgrim Homme wrote:
> 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.

I did a few more runs, and I'm getting about 18 messages/second (e.g.,
15,000 messages / 14 minutes; 75MG). Which doesn't sound so terrible.
My seen database, for example, is active.

> 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.
oprofile (thanks--I wasn't aware of this tool) shows

CPU: P4 / Xeon with 2 hyper-threads, speed 3000.14 MHz (estimated)
Counted GLOBAL_POWER_EVENTS events (time during which processor is not stopped) with a unit mask of 0x01 (manda
tory) count 100000
  samples|      %|
  2414674 55.8774 no-vmlinux
   985527 22.8059
   227336  5.2607
   204198  4.7253
   116551  2.6971 imapd
    82752  1.9149
    41630  0.9634
    31830  0.7366
    30574  0.7075 oprofiled
I'm not at all sure what that means, but it seems to show that a lot
of the time is inside the kernel, and libc-client, which I think is
part of the UW mailutils, is #2 on the list.


More information about the Info-cyrus mailing list