[Dovecot] Performance of Maildir vs sdbox/mdbox

[Timo Sirainen]

On 19.1.2012, at 19.08, Mark Moseley wrote:

>> namespace {
>>  separator = /
>>  prefix = "#mbox/"
>>  location = mbox:~/mail:INBOX=/var/mail/%u:INDEX=MEMORY
>>  inbox = yes
>>  hidden = yes
>>  list = no
>> }
>> 
>> 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.
>> 
>> --
>> Stan
> 
> It could be that I botched my test up somehow, but when I tested
> something similar yesterday (pointing the index at another location on
> the LDA), it didn't work.

Note that Stan used mbox format for INBOX, not mdbox.

> I was sending from the LDA server and
> confirmed that the messages made it to storage/m.# but without the
> real indexes being updated. When I checked the mailbox via IMAP, it
> never seemed to register that there was a message there, so I'm
> guessing that dovecot never looks at the storage files but just relies
> on the indexes to be correct. That sound right, Timo?

Correct. dbox absolutely relies on index files always being up to date. In some error situations it can figure out that it should do an index rebuild and then it finds any missing mails, but in normal situations it doesn't even try, because that would unnecessarily waste disk IO. (And there's of course doveadm force-resync to force it.)