On Mon, 2009-06-08 at 16:09 -0700, Timo Sirainen wrote:
Hmm. I suppose I could change Dovecot master so that if no imap/pop3
processes have been created yet, it would silently ignore the clock
move.
Implemented to v2.0. Maybe I'll backport it to v1.2 some day. From http://wiki.dovecot.org/TimeMovedBackwards :
Dovecot v2.0 finally tries to handle this a bit more gracefully. Its behavior when time moves backwards is:
* Existing imap and pop3 processes either sleep or die, just like
with older versions
* Master process stops creating new processes until either the
original time is reached, or after a maximum wait of 3 minutes.
* Other processes log a warning, but do nothing else.
* Timeouts are updated so that the timeout is executed
approximately at the original intended time. Dovecot v2.0 also notices when time unexpectedly jumps forwards. In that situation it logs a warning and also updates timeouts.
The reason why imap/pop3 processes get killed and new ones can't be created for a while is to avoid problems related to timestamps. Some issues are:
* Uniqueness of Maildir filenames and dbox global unique
identifiers relies on a growing timestamp
* Dotlock files' staleness is detected by looking at its mtime.
* Timestamps are stored internally all around in memory (as well
as in index files) and compared to current time. Those checks
may or may not be buggy if current time shrinks. While killing mail processes doesn't fully solve any of those issues, they're at least less likely to happen then.