[Dovecot] Performance of Maildir vs sdbox/mdbox

[Timo Sirainen]

On 18.1.2012, at 19.54, Mark Moseley wrote:

> I'm in the middle of working on a Maildir->mdbox migration as well,
> and likewise, over NFS (all Netapps but moving to Sun), and likewise
> with split LDA and IMAP/POP servers (and both of those served out of
> pools). I was hoping doing things like setting "mail_nfs_index = yes"
> and "mmap_disable = yes" and "mail_fsync = always/optimized" would
> mitigate most of the risks of index corruption,

They help, but aren't 100% effective and they also make the performance worse.

> as well as probably
> turning indexing off on the LDA side of things

You can't turn off indexing with dbox.

> --i.e. all the
> suggestions at http://wiki2.dovecot.org/NFS. Is that definitely not
> the case? Is there anything else (beyond moving to a director-based
> architecture) that can mitigate the risk of index corruption? In our
> case, incoming IMAP/POP are 'stuck' to servers based on IP persistence
> for a given amount of time, but incoming LDA is randomly distributed.

What's the problem with director-based architecture?