[Dovecot] dsync backup gets stuck... fails

[Jeff Gustafson]

On Tue, 2012-08-14 at 23:23 +0300, Timo Sirainen wrote:
> On 11.8.2012, at 0.54, Jeff Gustafson wrote:
> 
> > 	More dsync issues. We were running 2.1.7 and we updated to 2.1.9. Same
> > problem with both versions. 
> > 	I'm getting an error 75 on about 40 boxes out of 1800. It is the same
> > list of boxes every time we use 'dsync backup' to backup the server.
> > dsync seems to stop communicating to the backup box (over ssh). strace
> > just shows it sitting at a epoll_wait.
> 
> So you can easily reproduce this by running dsync for a specific user?

	Yes. There is a subset of mailboxes that always time out.

> > Once the program quits (times
> > out?), a 'du' shows the destination is smaller (200kbyte in one case).
> 
> As in, some of the mails didn't get synced? (doveadm fetch could be
> used to do a better comparison, file sizes don't necessarily mean
> anything.)

	True, I will dump out the mailboxes and see if it truly was incomplete.

> Those hangs are a little bit annoying to debug, and the whole code has
> been rewritten for v2.2 already in a way that should make the hangs
> pretty much impossible. Annoyingly v2.2 isn't ready yet..

	I have found a manual work around. I use rsync to get the files over to
the backup machines, then I let the backup script keep things up to
date. It is not the best way to go, but at least I have backups. I
suppose I can check the log and continue to rsync things over until 2.2
comes out.

			...Jeff