Running multiple instances of offlineimap

[Nicolas Sebrecht]

On Fri, Jun 22, 2012 at 08:27:14AM +0900, Daniel P. Wright wrote:

> I have been using offlineimap successfully for a while now on my work
> machine, but recently I decided I'd like to use it at home as well.  I
> frequently leave both machines on so that I can SSH home when at work,
> and vice versa.
> 
> I have offlineimap set to check my mail every three minutes or so.  When
> I started doing this on both machines, I ran into a problem.

I would not be confident enough into offlineimap to run it from more
than one machine at the same time.

Concurrent access to the same IMAP server from multiple locations
implies the server to mark some directories as read only while writing
from another IMAP session.  As a consequence, directories are going to
have a high level of changing state. I guess this is what offlineimap
might not handle very well.

In the past, offlineimap showed limitations in this area. AFAIR, nobody
strongly worked on your use case.  Also, this is hard to improve as IMAP
servers might behave differently.

I strongly suspect a lot of odd errors from various users (and IMAP
servers) come from concurrent access.

> I can only guess that the changes made on my work machine are synced to
> the server, but then within a minute or so my home machine does a sync
> and instead of getting all those changes down from the server it pushes
> its -- unmodified -- version back up!  My work machine then performs
> another sync with the server and the changes are undone.

Having mail metadata not reflected on all sides really looks like
something goes wrong either in offlineimap or your IMAP server (not
handling concurrent access as good as it should). Or both.

Either way, I recommend to not do this kind of configuration. At least,
you could start offlineimap every 30 minutes on each side with a 15
minutes gap between both and see if things go better.

-- 
Nicolas Sebrecht