Re: Questions about nnimap and cyrus->dovecot migration

[Daniel Pittman <daniel@rimspace.net>]

Steinar Bang <sb@dod.no> writes:
>>>>>> Daniel Pittman <daniel@rimspace.net>:
>
>> Technically, imapsync was mentioned there, which I have used and found
>> to be uniformly excellent.  It preserves all IMAP attributes by virtue
>> of working at the IMAP level, which is very effective, and handles
>> failure / interruption effectively.
>
> But it doesn't preserve the UIDs, which means that all the cached
> information in Gnus is useless, so that effectively it will be a new
> server as seen from Gnus.

Well, the cache is useless, but Gnus should handle things like marked
messages, etc, just fine.  nnimap certainly did when I moved from Cyrus
to Zimbra, the later of which does some very kooky things with UID
values.

So, you /should/ have all your data preserved, and only rebuilding of
the cache stuff to worry about.

> Hm... preserved flags or a new nnimap server, that's the question, I
> guess...?

I can't say for sure that the others don't preserve the appropriate
details, just that I have had very good experiences with imapsync.

> Also, I have some archive folders with more than 30k of messages.  I'm
> unsure if that will take a very long time.

I don't believe there is a significant performance cost to the IMAP
parts of imapsync compared to something that ran "in the background" of
the servers.

It does MD5 all the message content, though, which takes time.

> And another also: I planned to install dovecot on the same old server
> cyrus has been running.  But again: that's probably not worse than
> having dovecot run on a non-standard port for a while.

*nod*  Having to connect via IMAP is also a little awkward, but usually
not as dire is it might seem.

Anyway, my essential point in this response is: try the other tools,
maybe, and see if they work.  I can't say that they don't, and you can
fall back to imapsync at any stage, really...

Regards,
        Daniel