[Dovecot] Problem with huge IMAP Archive after Courier migration
preacher_net at gmx.net
Tue Jan 3 18:47:23 EET 2012
Actually I took a look inside the folders right after starting up and
waited for two hours to let Dovecot work.
Saving the whole Maildir into a tar on the same partition also took only
2 hours before.
But nothing did change and when looking at activities with top, the
server was idle, dovecot not indexing.
Also I wasn't able to drag new messages to the folder hierachy.
With courier it takes not more than 5 seconds to download the headers in
a folder containing more than 3.000 messages.
Stan Hoeppner schrieb:
> On 1/2/2012 10:17 AM, Preacher wrote:
>> So I forced to install the Debisn 7.0 packages with 2.0.15 and finally
>> got the server running, I also restarted the whole machine to empty caches.
>> But the problem I got was that in the huge folder hierarchy the
>> downloaded headers in the individual folders disappeared, some folders
>> showed a few very old messages, some none. Also some subfolders
>> I checked this with Outlook and Thunderbird. The difference was, that
>> Thunderbird shows more messages (but not all) than Outlook in some
>> folders, but also none in some others. Outlook brought up a message in
>> some cases, that the connection timed out, although I set the timeout to
>> Anyone a clue what's wrong here?
> Absolutely. What's wrong is a lack of planning, self education, and
> patience on the part of the admin.
> Dovecot gets its speed from its indexes. How long do you think it takes
> Dovecot to index 37GB of maildir messages, many thousands per directory,
> hundreds of directories, millions of files total? Until those indexes
> are built you will not see a complete folder tree and all kinds of stuff
> will be missing.
> For your education: Dovecot indexes every message and these indexes are
> the key to its speed. Normally indexing occurs during delivery when
> using deliver or lmtp, so the index updates are small and incremental,
> keeping performance high. You tried to do this and expected Dovecot to
> instantly process it all:
> If you don't know, that's a coal train car being dumped. 100 tons of
> coal in a few seconds. Visuals are always good teaching tools. I think
> this drives the point home rather well.
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