On 23/11/2012 06:07, Stan Hoeppner wrote:
On 11/22/2012 3:26 PM, 1st WebDesigns wrote:
Output of dovecot -n is as follows:
# 1.0.7: /etc/dovecot.conf
login_dir: /var/run/dovecot/login
login_executable(default): /usr/libexec/dovecot/imap-login
login_executable(imap): /usr/libexec/dovecot/imap-login
login_executable(pop3): /usr/libexec/dovecot/pop3-login
mail_privileged_group: mail
mail_location: mbox:~/mail:INBOX=/var/mail/%u
mbox_lock_timeout: 600
mail_executable(default): /usr/libexec/dovecot/imap
mail_executable(imap): /usr/libexec/dovecot/imap
mail_executable(pop3): /usr/libexec/dovecot/pop3
mail_plugin_dir(default): /usr/lib64/dovecot/imap
mail_plugin_dir(imap): /usr/lib64/dovecot/imap
mail_plugin_dir(pop3): /usr/lib64/dovecot/pop3
auth default:
passdb:
driver: pam
userdb:
driver: passwd
Are your mailboxes on NFS storage? You haven't stated on what storage
your mailboxes reside. NFS complicates locking. If you use an NFS
server, did anything on it change recently, such as an upgrade to RHEL5?
No they are not on NFS storage, the mailboxes are stored on the local
filesystem.
I found a thread stating RHEL5 has a bad FCNTL implementation that could
be related to your write lock delay problem. Try using dotlock only for
read and write and see if that helps. It has additional filesystem IO
overhead, but nothing like the many minutes of delay you have now.
mbox_read_locks = dotlock
mbox_write_locks = dotlock
Thank you I will try this. I did read that when using Postfix and
Dovecot, both systems should use a matching locking mechanism, which I
had already tried. However, I hadn't tried just dotlock, only FCNTL and
a combination of FCNTL and dotlock.
We upgraded from RedHat 4 to RedHat 5. The problem didn't exist with
RH4 and an even older version of Dovecot.
That may be, but you're surely not planning on downgrading back to RHEL4.
No, not at all.
When emails are stuck in the queue, doing this:
Dovecot doesn't use queues. It writes directly to the mailbox files.
lsof /var/spool/mail/<user>
These are mailbox files, your user inbox mbox files, not spool files.
Spool implies temporary storage. Don't let "spool" fool you. On
many/most systems /var/spool/mail is a link to /var/mail.
Yes that's correct.
shows the spool file in use by a pop3 login and the Dovecot deliver
process. Since changing mbox_lock_timeout from 300 to 600 the pop3
process eventually finishes before 600 seconds and the deliver process
is able to complete. I admit this is masking the problem rather than
solving it.
Does the larger timeout value completely eliminate the errors? If so
this may be the best outcome you can get with Dovecot 1.0.7, mbox
storage, on RHEL5, unless a different locking method fixes it.
Yes it completely eliminates the errors. If a pop3 connection has the
lock, the mail simply sits there and is eventually delivered in (less
than) 600 seconds. Whereas before, it would get deferred. When
re-delivery was attempted, it's possible that the box would be locked
again, and the mail would get deferred again, leading to a delay of
several hours on a busy day.
As discussed before our version of Dovecot is dated now, however it's
the version provided by RedHat and the version supported by our support
company (who aren't doing a great job, hence me posting here).
It's the version provided by RHEL5. RHEL6.3 has Dovecot 2.0.9. There
are 3rd party 1.2.x RPMs available for RHEL5.x as well as 2.x.x RPMs for
RHEL5.x.
What "support company"? If you're using RHEL, Red Hat provides the
support. That's the whole reason for "paying for" a Linux distro. What
is preventing you from upgrading to RHEL 6.3, the current release?
Which BTW is behind nearly all other distros WRT package versions. For
instance Debian stable has Dovecot 2.1.7 available in the backports repo.
Our server is with Rackspace, and RHEL5 is the OS they offered us as an
upgrade path from RHEL4. So they're getting the support from Red Hat
and we're getting the support from Rackspace.
