[Dovecot] migration 1.2.5 -> 2.0.5 load increased dramatically

[William Blunn]

On 06/10/2010 13:16, Ralf Hildebrandt wrote:
> * Ralf Hildebrandt<Ralf.Hildebrandt at charite.de>:
>    
>> During norml operation this morning we're seeing a significantly increased load on the IMAP server (factor 5, from 5 to 25).
>>
>> Does dovecot need to rebuild index files or perform other IO intensive operations after the upgrade?
>>
>> We're using Maildir
>>
>> Our monitoring shows increased "system" time. We're runnign fewer processes, the IO rate ist identical to yesterday, memory usage is identical.
>>      
> I found the reason: My excessive number of ca-certificates!
>
> dovecot-lda invoke doveconf, which in turn needs a whooping 1.2s wallclock time to parse the config!
>
> I pruned the ca-certificates file and removed ALL ca-certificates but the ones that belong to the certificate chain for postamt.charite.de

Hello Ralf,

Glad to see you found out what the problem was.

I was just wondering if this episode suggested any changes which may be 
helpful. I am not an expert on the issue you discovered, so I came up 
with some questions which might help guide us.

Do you feel that the problem was more that you were feeding Dovecot an 
unusually large certificate pack, or that your certificate pack was 
reasonable and Dovecot should be able to cope better with packs of this 
size?

Should we write something in the Dovecot wiki about it?

Should we need to suggest an enhancement to Dovecot?

Regards,

Bill