[Dovecot] dovecot evaluation on a 30 gb mailbox

[Eric Shubert]

Rajesh M wrote:
>> Rajesh M wrote:
>>>> Rajesh M wrote:
>>>>> eric
>>>>>
>>>>> i studied LDA a bit
>>>>  >
>>>>> if i use lda that means all my 5000+ users' email index files will be
>>>>> continuously updated when every email arrives -- means a lot of writes
>>>>> to
>>>>> disk ... is that correct ?
>>>> Yes, but I think you make it sound worse than it is. Updating the index
>>>> as each email arrives doesn't involve rebuilding the whole index like
>>>> what happens at login. It only updates what's there instead of
>>>> rebuilding the whole thing. I can't speak from experience, but I expect
>>>> that it's very efficient, and you'll never notice any increased load on
>>>> the machine. Perhaps the equivalent of adding journaling to a
>>>> filesystem. You can ask the dovecot list to verify this.
>>>>
>>>> Also, it just occurred to me that if you're using ext3, you should be
>>>> sure to optimize the filesystem. Off hand, I'd use the noatime and
>>>> nodiratime mount options (man mount) and dir_index filesystem option
>>>> (man tune2fs).
>>>>
>>>>> if yes then i dont want that since only around 200 or so people out of
>>>>> the
>>>>> above 5000 use webmail.
>>>> Just to be clear, it affects all imap usage, not only webmail (although
>>>> your uses may not use imap other than webmail).
>>>>
>>>>> i will study a some more and revert
>>>> I hope you can figure a way to try this out. I expect that QMT's move
>>>> to
>>>> dovecot in the future will include the deliver LDA, and your work here
>>>> will be a big help getting us there.
>>>>
>>>> Let me know if I can be of any further help.
>>>>
>>>> --
>>>> -Eric 'shubes'
>>>>
>>>
>>> hi eric
>>>
>>> few questions
>>>
>>> i wil enable lda exclusively for this one 30 gb email box using .qmail
>>> file see the performance improvement .. is that ok ?
>> I believe that would be fine.
>>
>>> can i safely enable atime for this user maildir  ?
>> Sure. That's simply a performance consideration. I don't believe that
>> atime is used for much of anything, so either atime or noatime is safe.
>> noatime is just a little faster because the inode (where that piece of
>> information is stored) doesn't need to be updated each time a file is
>> accessed.
>>
>>> thanks for your help
>> Sure. I'm eager to see your results.
>>
>> --
>> -Eric 'shubes'
>>
> 
> 
> hi eric
> 
> this is what i plan to do
> 
> as per
> http://wiki.dovecot.org/LDA/Qmail
> 
> i need to enter the following line in a .qmail file under the Maildir
> directory of the user
> |/var/qmail/bin/preline -f /usr/local/libexec/dovecot/deliver -d $EXT@$USER

the location is /usr/libexec/dovecot/deliver on my system.

> i would add an email forward using qmailadmin web interface (which creates
> the .qmail file) and then manually edit the .qmail file and put the above
> line in it (so that ownership and permissions are taken care off)

That sounds ok. The permissions/ownership I'm seeing on .qmail files is:
-rw-------   1 vpopmail vchkpw   101 Mar 26  2008 .qmail

> now i would also need to edit the dovecot.conf file
> could you guide me on what changes do i need to dovecot.conf file ?

Others on this list would be more help than me regarding this. From the 
looks of it though (after browsing the dovecot.conf file, which is well 
documented btw) I don't think you'd need to change a thing. We'll 
certainly find out if that's the case or not. I'd just give it a go. 
Perhaps on a test account initially. ;)

-- 
-Eric 'shubes'