[Dovecot] lstats on all files in Maildir when opening an e-mail.

[Tan Shao Yi]

Hi Daniel,

Did you just implement Maildir++ quotas? If you did, it may be busy 
recalculating the "maildirsize" file for the first time.

There's an interesting read on how/when this is done: 
http://www.inter7.com/courierimap/README.maildirquota.html

Otherwise you may need to trace what the processes are really doing on 
disk.

I'm sorry I can't share with you our system load; we are running a 
department server with about 30-odd users (and it's on a SAN!)... so I 
don't think the load that we have is really that significant.  :P

Cheers,
TAN Shao Yi

On Tue, 27 Feb 2007, Daniel Watts wrote:

> Hi Tan Shao,
>
> Thanks for the fast reply =)
> My sysadmin also found that link and has tried putting it into place. Seems 
> like it has solved the problem nicely.
>
> We are still seeing 99%-100% disk usage though which is a little worrying:
>
> Device:    rrqm/s wrqm/s   r/s   w/s  rsec/s  wsec/s    rkB/s    wkB/s 
> avgrq-sz avgqu-sz   await  svctm  %util
> sda          4.80  16.50 86.50 34.70 3464.80  730.60  1732.40   365.30 
> 34.62    27.38  224.38   8.25 100.04
>
> Device:    rrqm/s wrqm/s   r/s   w/s  rsec/s  wsec/s    rkB/s    wkB/s 
> avgrq-sz avgqu-sz   await  svctm  %util
> sda          4.00   8.99 74.93 33.57 2618.98 1175.72  1309.49   587.86 
> 34.98    20.10  187.70   9.21  99.94
>
> Device:    rrqm/s wrqm/s   r/s   w/s  rsec/s  wsec/s    rkB/s    wkB/s 
> avgrq-sz avgqu-sz   await  svctm  %util
> sda          1.80  36.84 49.25 47.75 1508.71 1114.61   754.35   557.31 
> 27.05    41.22  424.25  10.32 100.10
>
> Do you get think kind of load when Dovecot is busy? We have about 50 dovecot 
> processes running.
>
> Best wishes,
> Daniel
>
> Tan Shao Yi wrote:
>> On Tue, 27 Feb 2007, Daniel Watts wrote:
>> 
>>> Hi guys -
>>> So what can we use instead? We've just had 2 days downtime because Dovecot 
>>> was using 100% of the disk. As reported above - every action on a user 
>>> mailbox seems to lstat every file in the user's home.
>>> 
>>> So we've disabled quota completely and these millions of lstats have 
>>> stopped.
>>> 
>>> We're running virtual users (all under a vmail system user) so fs quota is 
>>> not workable. What do you recommend for a Maildir?
>>> 
>>> This is bad enough to almost work having Dovecot throw a:
>>> WARNING: dirsize not recommended with Maildir format.
>> 
>> 
>> Hi Daniel,
>> 
>> I am now using Maildir++ quotas (http://wiki.dovecot.org/Quota/Maildir).
>> 
>> Cheers.
>> 
>