[lvs-users] High Traffic IMAP deployment

Jose Ildefonso Camargo Tolosa ildefonso.camargo at gmail.com
Sun Aug 15 02:15:00 BST 2010


On Fri, Aug 13, 2010 at 2:00 PM, Tracy Reed <treed at ultraviolet.org> wrote:
> On Fri, Aug 13, 2010 at 11:09:54AM -0430, Jose Ildefonso Camargo Tolosa spake thusly:
>> I think they are pretty much the same, maybe, dovecot a little faster
> Count me as another vote for dovecot. It works great.
>> Nothing new, except, maybe, the replication thing, Cyrus suggest the
>> use of Perdition (which can be very problematic, specially with
>> SSL/TLS related issues).
> Around 2000 I migrated a large (for the time) corporate mail server
> from wu-imap/mbox to courier (if I recall correctly)/Maildir. It was
> not possible to convert all of the mailboxes at once due to the large
> amount of time it would have taken (and also because a desktop config
> setting was needed due to how broken Outlook was with IMAP
> namespaces). So I ended up running both IMAP servers at once on
> unusual port numbers with perdition running on the normal IMAP
> port. Then as each user's mail store was converted I would add them to
> the perdition config and perdition would route them to the appropriate
> IMAP server. It worked great.

Yes, perdition *does* work, but it only support LDAPv2, I had to
modify the LDAP server configuration.

One question: what was the MTA on that setup? (that support having
mixed mailboxes formats for different users).

> Ever since then I have always said that if I ever needed to really
> scale up IMAP serving across a number of machines I would front it
> with perdition.
>> Furthermore, Dovecot has this:
>> http://wiki.dovecot.org/PasswordDatabase/ExtraFields/Proxy
>> Which replaces perdition.
> Oooh...neat! I'll have to remember to give this a try if I ever have
> to scale up IMAP.
> In other news, I am on the verge of un-recommending anyone use
> RedHat's Piranha setup. Its behavior is just inexplicable
> sometimes. And the GUI let me accidentally create invalid
> configurations. I may well replace my current Piranha based load
> balancer setup with a more standard lvs/ldirectord type setup.

Fortunately: I don't use RedHat, unless forced by a client.  I like
Debian the best for this kind of things, and, maybe, Ubuntu.

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