[Dovecot] Dovecot Deliver CPU usage

[Aravind Divakaran]

On Thu, 3 Dec 2009 09:05:21 -0600, Timo Sirainen <tss at iki.fi> wrote:
> On Dec 3, 2009, at 5:50 AM, Aravind Divakaran wrote:
> 
>>> strace -tt would have actually been also more helpful, so it would
have
>>> included timestamps. Are you using NFS or something similar for your
>>> filesystem in /home? The strace does show that Dovecot seems to be
>>> reading
>>> from a file that it just wrote to, so there's something non-optimal
but
>>> it
>>> necessarily shouldn't be that slow.
>> 
>> You can find my strace with timestamp on the below link.
>> 
>> http://pastebin.com/m2942fbdd
> 
> That's only 400 milliseconds. I thought the delivers would be running
for
> at least a few seconds? Can you show such a strace -tt?
> 
>> My /home partition using san storage with ocfs filesystem.
> 
> Anyway I suppose this could be the reason, if the problem is the reads..
> 
> You could also try if it helps when you increase this in
> src/deliver/deliver.c:
> 
> #define MAIL_MAX_MEMORY_BUFFER (1024*128)
> 
> to
> 
> #define MAIL_MAX_MEMORY_BUFFER (1024*1024*100)
> 
> i.e. 100 MB (or whatever is large enough for most mails).

I had made the changes for MAIL_MAX_MEMORY_BUFFER and installed the new
dovecot. 

I was monitoring my mail server for past few days. Today i experienced the
same problem

My log file shows

Dec 14 12:38:19 server01 dovecot: deliver(user1 at example.com): Created
dotlock file's timestamp is different than current time (1260774499 vs
1260774377): /home/vmail/example.com/user1/dovecot-uidlist
Dec 14 12:38:19 server01 dovecot: deliver(user2 at example.com): Created
dotlock file's timestamp is different than current time (1260774499 vs
1260774377): /home/vmail/example.com/user2/dovecot-uidlist

The above erros will show when i change the maxproc from 4 to default in
postfix. At this time dovecot deliver process is using lot of cpu.

Dec 14 12:46:04 server01 postfix/pipe[1870]: 57489E913:
to=<user1 at example.com>, orig_to=<user2 at example.com>, relay=dovecot,
delay=1703, delays=1369/328/0/5.9, dsn=5.7.0, status=bounced (permission
denied. Command output: Not enough disk space )

As my hardisk has enough space, why dovecot is giving this error?

-Aravind