[Dovecot] Performance of Maildir vs sdbox/mdbox

[Timo Sirainen]

On 19.1.2012, at 6.39, Stan Hoeppner wrote:

>> You're going to run into NFS caching troubles with the above split
>> setup. I don't recommend it. You will see error messages about index
>> corruption with it, and with dbox it can cause metadata loss.
>> http://wiki2.dovecot.org/NFS http://wiki2.dovecot.org/Director
> 
> Would it be possible to fix this NFS mdbox index corruption issue in
> this split scenario by using a dual namespace and disabling indexing on
> the INBOX?  The goal being no index file collisions between LDA and imap
> processes.  Maybe something like:
> 
> namespace {
>  separator = /
>  prefix = "#mbox/"
>  location = mbox:~/mail:INBOX=/var/mail/%u:INDEX=MEMORY
>  inbox = yes
>  hidden = yes
>  list = no
> }
> namespace {
>  separator = /
>  prefix =
>  location = mdbox:~/mdbox
> }
> 
> Client access to new mail might be a little slower, but if it eliminates
> the index corruption issue and allows the split architecture, it may be
> a viable option.

That assumes that mails are only being delivered to INBOX (i.e. no Sieve or +mailbox addressing). I suppose you could do that if you can live with that limitation. Slightly better for performance would be to not actually keep INBOX mails in mbox format but use snarf plugin to move them to mdbox.

And of course the above still requires that for imap/pop3 access the user is redirected to the same server every time. I don't really see it helping much.