[Dovecot] dsync backup gets stuck... fails

[Timo Sirainen]

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?

> 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.)

> 	Has anyone else seen an exit code of 75? Nothing in the documentation
> mentions what exit code 75 could mean.

"temporary failure".

> 	What can I do to help the developers locate the bug?

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..