[Dovecot] Outlook 2010 very slow when using IMAP - are there any tweaks?

[Kaya Saman]

On Tue, Jul 3, 2012 at 11:51 AM, Kaya Saman <kayasaman at gmail.com> wrote:
> On Tue, Jul 3, 2012 at 11:37 AM, Charles Marcus
> <CMarcus at media-brokers.com> wrote:
>> On 2012-07-03 3:12 AM, Kaya Saman <kayasaman at gmail.com> wrote:
>>>
>>> However this is a clean server with plenty of space left on the pool
>>> allocated for mail and it's additionally using ZFS too.
>>
>>
>> What OS? ZFS implementation/version? How is mail stored (maildir? mbox?)
>>
>> While I don't think this is your problem, just fyi, my understanding is that
>> it is fairly easy to implement ZFS wrong (which would cause serious
>> performance problems), and that the only decent ZFS implementation is Suns
>> (ie, what ships with Nexenta), or the latest FreeBSDs...
>>
>> Also, my understanding is that ZFS isn't the snappiest of filesystems even
>> when properly configured (you trade performance for data integrity).
>>
>> Personally, I'd recommend trying this on a traditional FS (XFS or Reiserfs
>> for maildir) and see if that changes things.
>
> FreeBSD 8.2 x64 using Maildir. ZFS is perfect no worries with that!!!
> Additionally the system is on a VMware cluster which is also fine -
> have checked all as diagnostics.
>
> The usage here is minimal, and since I also use ZFS at home too with
> quite a larger file system then at work (I know I know) and really
> hammer the heck out of it there is no issue.
>
>>
>>
>> On 2012-07-03 3:12 AM, Kaya Saman <kayasaman at gmail.com> wrote:
>>> The point is that I am monitoring using nload as well as other things
>>> and the maximum bandwidth being got with Outlook is a few Mbps burst,
>>> average 50kbps; while with T-Bird I get way over 130Mbps?
>>
>> Congrats - there's your problem... now you need to find out *why* this is so
>> slow... most likely a tcp dump analysis of a session is the only way - I
>> think there are people here who could help you analyze one (but not me,
>> sorry)...
>>
>
> Yeah, it seems to be M$ implementation of IMAP. I don't think that
> there's anything anyone can do.... Outlook seems to wait after each
> transmission (found using Wireshark).
>
>>
>> On 2012-07-03 3:41 AM, Kaya Saman <kayasaman at gmail.com> wrote:
>>> The PST's seem to be stored on local hard disk too.
>>
>> 'Seem' to be? You need to make sure, because if they aren't that could
>> definitely cause, or at least contribute to this kind of problem.
>>
>
> It is definitely stored locally!
>
>> --
>>
>> Best regards,
>>
>> Charles
>
> Regards,
>
>
> Kaya


Ok now probably related to this is that some folders are not able to copy??

While dragging one folder from Outlook PST to the Dovecot IMAP server
in Outlook 2010, the transfer keeps bombing out?

In the logs all I see are:

: Error: stat(/mail/AD_Mail//

errors.

My user was actually testing by copying the Inbox with many
subdirectories into the INBOX on dovecot.


Is this another Outlook related quirk or is it something serverside
which I need to change?


Regards,


Kaya