LMTP re-reading all messages

[Florent Bautista]

Hi all,

I have a little problem with Dovecot 2.1.17 and MailDir accounts.

I was using a shared file system (MooseFS), and all was pretty stable.

Now I'm switching to CephFS, and Dovecot LMTP have problem to deliver mails.

Very often, on large accounts, LMTP processes are running for a few hours
before delivering the message.

When I strace it, I can see that they are reading (open and stat
operations) ALL the messages of the account.

I was thinking to an index problem, but I think that after hundreds of
delivered mails, indexes are rebuilded and problem should be solved. But
not.

The same way, If user connects to IMAP, a lot of IMAP processes get stuck
on "getquotaroot" command (multiple processes for a single account).

The previous FS didn't support mmap, so I disabled it. The new one supports
it, so I enabled it, but it does not solve the problem.

Do you have an idea of why Dovecot (LMTP or IMAP) spend a lot of time on
large accounts ?

Thank you a lot.
Florent