[Dovecot] ZFS Index corruption and Connection reset by peer

[Timo Sirainen]

On ti, 2010-06-08 at 14:20 +0200, Philippe Chevalier wrote:

> dovecot: IMAP(<user>@domain.org): Corrupted transaction log file /home/<user>/Mail/Maildir/INBOX/dovecot.index.log seq 13: record size too small +(type=0x0, offset=5560, size=0) (sync_offset=5652)
..
> After some digging, I "solved" this problem with mmap_disable = yes in
> dovecot.conf. Index corruption doesn't seem to occur anymore.
> 
> Is this normal? I thought this problem occured only on NFS filesystem
> and eventually on old versions of ZFS. Hasn't this been fixed?

Apparently it doesn't work perfectly..

> Is there an option in ZFS that would allow mmap calls without
> corruption. Has it something to do with compression ?

I've no idea about ZFS.

> Other problem, that I have been unable to solve so far, is that a lot of
> entries show up in my logs about :
> 
> dovecot: imap-login: net_disconnect() failed: Connection reset by peer

This means close() failed with:

[ECONNRESET]	The underlying object was a stream socket that was
			shut down by the peer before all pending data was
			delivered.

This is the first time I've heard of this happening.. I see this shows
up the first time in FreeBSD 6.3 man pages. Hmm. I don't like it. I
guess I could work around it, but I think I'll first go complain about
it to FreeBSD people.