Well, I'm not paying for it. And I've managed to fix the comedy stability I've come across so far, but you're right- I haven't really loaded the system up yet.

My rationale is that I want a filesystem I can share between several servers, reducing the points of failure as far as I can down. We've got a large iSCSI SAN we've already bought for other projects, and I'd like to use that for our storage. So using NFS, I'd have to have another server in front of my SAN that act as an NFS server (presuambly as a single point of failuire), and the mail servers as NFS clients. I'd rather have the servers talk to the SAN directly. Besides, NFS never really works for me, but I'm sure I could overcome that.

Anyway, I don't think it's a GFS problem so far.

David

-----Original Message----- From: dovecot-bounces@dovecot.org [mailto:dovecot-bounces@dovecot.org] On Behalf Of Justin McAleer Sent: 05 April 2007 13:37 To: dovecot@dovecot.org Subject: Re: [Dovecot] Problems using GFS2 and clustered dovecot

David Craigon wrote:

...

I am trying to use dovecot. I've got a GFS2 shared volume on two servers with dovecot running on both. On one server at a time, it works.

Sorry to not answer your question directly, but do you have a good reason to be using GFS instead of NFS? We experimented with GFS last year (granted, not GFS2), and found its performance pretty horrible and its stability comically bad... had we been paying for it, however, it wouldn't have been funny. OCFS2 was better, but still unreliable. Lustre was the best we found (it worked, at least), but it required a lot of hardware/admin overhead. We tried other clustering filesystems as well, and none of them was worth the trouble.

...

The test I am trying is to attach two mail programs (MUA) via IMAPS (Thunderbird and Evolution as it happens). I've attached one mail program to each IMAPS server. I am trying to move emails around in one program (from folder to folder), and then checking it on the other program. I'm testing in effect how it would work if my users log on twice and end up on different servers.

I seem to suffer from never ending index file corruption:

Apr 4 16:55:49 mailstore-b dovecot: IMAP(david@everybody-loves.craigon.co.uk): Corrupted transaction log file

/mnt/mailstore/e/everybody-loves.craigon.co.uk/d/david/.fish/dovecot.i

...

nd ex.log: end_offset (284) > current sync_offset (104) Apr 4 16:55:49 mailstore-b dovecot: IMAP(david@everybody-loves.craigon.co.uk): broken sync positions in index file

/mnt/mailstore/e/everybody-loves.craigon.co.uk/d/david/.fish/dovecot.i

...

nd ex Apr 4 16:55:49 mailstore-b dovecot: IMAP(david@everybody-loves.craigon.co.uk): fscking index file

/mnt/mailstore/e/everybody-loves.craigon.co.uk/d/david/.fish/dovecot.i

...

nd ex Apr 4 16:55:49 mailstore-b dovecot: IMAP(david@everybody-loves.craigon.co.uk): Fixed index file

...

nd ex: log file sync pos 1,284 -> 1, 104 Apr 4 16:55:50 mailstore-b dovecot: IMAP(david@everybody-loves.craigon.co.uk): Unexpected

/mnt/mailstore/e/everybody-loves.craigon.co.uk/d/david/.fish/dovecot.i transaction log

...

desync with index

/mnt/mailstore/e/everybody-loves.craigon.co.uk/d/david/.fish/dovecot.i

...

nd ex Apr 4 16:56:18 mailstore-b dovecot: IMAP(david@everybody-loves.craigon.co.uk): Transaction log file

/mnt/mailstore/e/everybody-loves.craigon.co.uk/d/david/.fish/dovecot.i

...

nd ex.log: marked corrupted

This happens pretty quickly. I can also get message duplication- if I move a message from one server to another, I can get a message in the original folder and the destination folder.

I am using RC28. I have tried using fcntl locking and dotlocking with equal lack of success.

Can anyone offer any advice?

David

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