[Dovecot] reproducible dsync backup panic (dovecot 2.2.7)

[Timo Sirainen]

On 17.12.2013, at 11.54, Peter Benko <pbopbo at freemail.hu> wrote:

> I'm receiving a reproducible dsync backup panic for some of my users. The error message is as follows:
> 
> dsync-remote(user@<removed>): Panic: file dsync-brain-mailbox-tree-sync.c: line 111 (dsync_brain_mailbox_tree_sync_change): assertion failed: (brain->no_backup_overwrite)

Can you get it to dump core and use

gdb /usr/bin/doveadm core
bt full
fr 5
p *change

> The command I'm using to back up individual user's mail is something like:
> 
> sudo -u vmail dsync -v -u user at server.com -R backup ssh -i sshid-file login at server.com sudo -u vmail dsync -v -u user at server.com

Probably an easier way would be if you could copy the local and remote mdboxes to e.g. /tmp/mdbox-local and /tmp/mdbox-remote. Then you should be able to do:

gdb --args doveadm -o mail=mdbox:/tmp/mdbox-local backup -R mdbox:/tmp/mdbox-remote
run
bt full
fr 5
p *change

Oh, and in any case this would be helpful in figuring out the problem. Run these on both local and remote servers and send the output to me:

doveadm mailbox status -u user at domain 'guid uidvalidity uidnext' '*'
doveadm dump /mail/mailboxes/domain/user/dovecot.mailbox.log