dovecot - Jan 2006 - very slow imap opens in pine after moving maildirs to new drive

Hi,

I've been running dovecot-0.99.10 for the past several years, with
virtually no problems.  Lately, I noticed that the filesystem holding my
users' imap maildirs was getting close to full.  So... last night, I
used tar to copy /var/spool/imap to a new drive (9G scsi, reiserfs) that
I then mounted under /var/spool/imap (after moving the old dir aside).

After the move, what would take pine a handful of seconds, with the load
average barely breaking .40, now takes several minutes, with a load
average spike to nearly 3.

I must admit to being rather puzzled by this, as I would not have
expected the move to result in worse performance.  Do I need to figure
out what the index file names are, and delete those?  Any suggestions
greatly appreciated - as even closing pine now takes nearly 5 minutes,
whereas when dovecot talks to my old imap dir (I've tested this),
closing the session takes no more than 10 seconds.

server is Mandrake 9.1, 2.4.21-0.13mdkenterprise, P4 2.6GHz, 1G RAM 9G
U2W SCSI system disk, 9G U2W SCSI (and big*ss IDE drive for /users).  Each
of the scsi drives is on its own aha-2940UW controller.

Filesystem on old imap location (/var filesystem) is reiserfs, same as
that on new dedicated disk.

Thanks much,

Dave

-- 
--------------------------------------------------------
Dave Lugo   dlugo at etherboy.com    LC Unit #260   TINLC
Have you hugged your firewall today?   No spam, thanks.
--------------------------------------------------------
Are you the police?  . . . .  No ma'am, we're sysadmins.

Dave Lugo wrote:
> Hi,
> 
> I've been running dovecot-0.99.10 for the past several years, with
> virtually no problems.  Lately, I noticed that the filesystem holding my
> users' imap maildirs was getting close to full.  So... last night, I
> used tar to copy /var/spool/imap to a new drive (9G scsi, reiserfs) that
> I then mounted under /var/spool/imap (after moving the old dir aside).
> 
> After the move, what would take pine a handful of seconds, with the load
> average barely breaking .40, now takes several minutes, with a load
> average spike to nearly 3.
> 
> I must admit to being rather puzzled by this, as I would not have
> expected the move to result in worse performance.  Do I need to figure
> out what the index file names are, and delete those?  Any suggestions
> greatly appreciated - as even closing pine now takes nearly 5 minutes,
> whereas when dovecot talks to my old imap dir (I've tested this),
> closing the session takes no more than 10 seconds.
> 
> server is Mandrake 9.1, 2.4.21-0.13mdkenterprise, P4 2.6GHz, 1G RAM 9G
> U2W SCSI system disk, 9G U2W SCSI (and big*ss IDE drive for /users).  Each
> of the scsi drives is on its own aha-2940UW controller.
> 
> Filesystem on old imap location (/var filesystem) is reiserfs, same as
> that on new dedicated disk.
> 

tried:

   . rm'ing .imap.index*
       no improvement noted

   . putting both scsi disks on same controller
       no improvement noted


I'm about to try placing the maildirs on the IDE disk used for /users, 
to see if that makes a difference.

FWIW, Thunderbird (even after I remove the .msf file for my inbox) still 
opens MUCH faster than pine; less than a minute for the former, vs 
nearly 5 minutes for the latter.

I'm getting rather more concerned, because if dovecot refuses to play 
nice on all but the fs I originally saved the maildirs to, I'm going to 
run out of space within days.


-- 
--------------------------------------------------------
Dave Lugo   dlugo at etherboy.com    LC Unit #260   TINLC
Have you hugged your firewall today?   No spam, thanks.
--------------------------------------------------------
Are you the police?  . . . .  No ma'am, we're sysadmins.

Dave Lugo wrote:
> users' imap maildirs was getting close to full.  So... last night, I
> used tar to copy /var/spool/imap to a new drive (9G scsi, reiserfs) that
> I then mounted under /var/spool/imap (after moving the old dir aside).
What was the old fs? I remember something in the reiserfs FAQ about bad
performance if you tar-copied from some other fs... ah, yes:
http://www.namesys.com/faq.html#file-ordering-speed