[Dovecot] Dovecot 1.2/2.0 coexistence guide?

[Tom Talpey]

On 12/9/2010 10:31 AM, Ron Leach wrote:
> Tom Talpey wrote:
>> On 12/5/2010 2:25 PM, Timo Sirainen wrote:
>
>>> It's also safe to run v1.2 and v2.0 in parallel, even accessing the
>>> same index files.
>>>
>>
>> So, I just installed 2.0.8 on a separate server and deployed a test user
>> or two.
>
> Did you leave both servers up (that v2 can co-exist and use the same
> indexes is quite a promising route for live-migration), and let v2
> 'look' at the v1 mails? I think this would mean that only Dovecot 2
> would need to be reconfigured.
>
> Or did you move the v1 mails across to the v2 server (and if you did
> that, did you have any problems)? Moving the mails also implies
> reconfiguring the MTA as well, I think, so this step isn't only a
> Dovecot reconfiguration issue.

I ended up not trying to deploy both 1.2 and 2.0 dovecot servers on the
same machine. Even after mangling the various configure options to let
the bin, sbin, lib and libexec directories coexist, the /var and /etc
dirs were still an issue, and in the end I didn't want to have all my
path settings tweaked, then have to un-tweak them to actually migrate.
Also, there's the issue of multiple network listeners so I'd have to
mangle ports, too.

I don't have much of an issue with MTA integration because I'm just
using fetchmail to perform that. My MTA is just dovecot deliver, and
it's easy to redirect it with fetchmailrc and dovecot settings. So I
just cloned the victim maildir tree, set "keep" in fetchmail, and
tested.

In the end, the testing was so successful that I just cut the server
over after a couple of days. Mostly I waited just to be confident that
I had all the dovecot.conf settings finalized. The doveconf tool did
a pretty good job of it, but there were a few new settings to try,
and I had an explicit auth_executable line that didn't carry forward
to the new binaries. All were quite straightforward.