[Dovecot] How to upgrade a running Dovecot?
c.d.wakelin at reading.ac.uk
Fri Oct 5 12:35:12 EEST 2007
Mike Brudenell wrote:
> Yes... However the dovecot.conf configuration file includes a comment
> which says this:
> # Should all IMAP and POP3 processes be killed when Dovecot master process
> # shuts down. Setting this to "no" means that Dovecot can be upgraded
> # forcing existing client connections to close (although that could also be
> # a problem if the upgrade is eg. because of a security fix). This however
> # means that after master process has died, the client processes can't
> # to log files anymore.
> #shutdown_clients = yes
> This implies it *is* possible to upgrade the software without breaking
> existing live connections. I'm trying to get confirmation of this along
> with any side-effects -- for example the comment seems to warn that
> pre-existing connections will no longer be able to write to the logfiles
> after the changeover?
> Mike B-)
I think you're safe enough to do this if the upgrade is between similar
versions (but not, say, between Dovecot 1.0.x and 1.1.x where things
like the index files format changed).
Yes, you lose the logging, but I've not known it cause us any problems
when we've done it. I think the most likely issue is where a client has
multiple IMAP connections and some are to the new version and some are
to the old and it might get upset if they appear different in some way
(e.g. a version war over indexes).
It *is* neater to kill off the older version processes though. Most of
our clients (<cough>Outlook Express </cough> and Prayer Webmail) will
reconnect automatically anyway.
Christopher Wakelin, c.d.wakelin at reading.ac.uk
IT Services Centre, The University of Reading, Tel: +44 (0)118 378 8439
Whiteknights, Reading, RG6 2AF, UK Fax: +44 (0)118 975 3094
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