[Dovecot] Migrating to mdbox

[Timo Sirainen]

On 9.3.2011, at 18.02, Chris Wilson wrote:

> I think it would be a good idea for me to move from mbox to mdbox, as I 
> have 57,000 messages in my inbox, and clients hang for a minute whenever 
> they request a CHECK, or Dovecot feels the need to run one itself.

mbox_very_dirty_syncs=yes should get rid of this problem even without switching to mdbox.

> This error occurs every time I run dsync, and I understand it, so I've 
> elided it:
> 
> dsync(chris): Error: open() failed with mbox file /home/chris/mail/admin: 
> Permission denied

So that is intentional?..

> I don't understand the following errors from dsync (2.0.9):
> 
> chris at one-mail(~)$ sudo dsync -v -u chris backup mdbox:/home/chris/mdbox
> dsync(chris): Error: Next message unexpectedly corrupted in mbox file 
> /home/chris/mail/spam at 404513741

mbox bug. Same would happen if you tried to read that same mail via imap. It fixed itself automatically though.

> dsync(chris): Warning: Transaction log file 
> /home/chris/mail/.imap/spam/dovecot.index.log was locked for 252 seconds

Normal with a large mbox.

> dsync(chris): Info: spam: only in source
> dsync(chris): Info: temp: only in source
> dsync(chris): Info: Sent: only in source
> dsync(chris): Info: addressbook: only in source
> dsync(chris): Info: sent-mail-sep-2008: only in source
> dsync(chris): Info: sent-mail-oct-2010: only in source
> dsync(chris): Info: INBOX.Sent: only in source
> dsync(chris): Info: sent-mail: only in source
> dsync(chris): Info: INBOX.Trash: only in source

Just saying that destination doesn't have these mailboxes yet.

> chris at one-mail(~)$ sudo dsync -v -u chris backup mdbox:/home/chris/mdbox
> dsync(chris): Info: spam: only in source
> dsync(chris): Info: spam: only in dest
..
> dsync(chris): Error: Failed to sync mailbox spam: Mailbox doesn't exist: 
> spam
..
> Note: how is it possible for the same folder to be "only in source" and 
> "only in dest"?

I think they have different GUIDs, or maybe Dovecot failed to get one of their GUID. Dsync works with mailbox GUIDs, not names. Anyway, I don't really know why it would suddenly lose one of them.

> chris at one-mail(~)$ sudo dsync -v -u chris backup mdbox:/home/chris/mdbox
> dsync(chris): Info: spam: highest_modseq changed: 2 != 3
> 
> Now the latter is all I get whenever I run dsync. Is it broken?

Nope. The modseq syncing isn't really perfect. So everything should be synced now.