[Barry, question for you further down]
On Wed, Jan 23, 2002 at 03:22:43PM -0800, Darrell Fuhriman wrote:
Right now, it's essentially impossible to have more than one machine doing Mailman processing. (Yes, there are ways to hack around it, but they get ugly quickly.)
I have a mail server which automatically rewrites mailman lists envelope tos to go to the mailman only mail server.
It's also impossible to have the web interface on any machine other than the machine where list explosion happens. This is
Yes and no. Back in the mm2.0 days, one of my requirements for upgrading mailman on sourceforge.net was to have redundancy and load balancing.
You _can_ export ~mailman over NFS. The problem was that with linux 2.2 back then, under very high load and lock contention (I sent 1000 messages to the same list on the two different mail servers to force them to fight over ~mailman/lists/listname/config.db). I was able to find a race condition in NFS rename/unlinks which caused 3 messages out of the 2000 to bounce. (I don't know if it's under NFS only, but after getting config.db corruption on 3 messages, when mailman renames the ocnfig.db.last to config.db, there was a very small time window when there was no config.db, and my exim with auto list detection failed to stat the config.db, and stated that the list didn't exist).
For more details, see my this message in the archives: From: Marc MERLIN <marc_news@valinux.com> To: mailman-developers@python.org Subject: Doing load balancing with mailman Message-ID: <20001117130521.V9808@marc.merlins.org> Date: Fri, 17 Nov 2000 13:05:21 -0800
and the following thread:
From: Marc MERLIN <marc_news@valinux.com> To: mailman-developers@python.org Subject: about qrunner and locking Message-ID: <20001207162234.D25463@marc.merlins.org> Date: Thu, 7 Dec 2000 16:22:34 -0800
Barry: With the new qrunner infrastructure, does qrunner still need to lock the lists during delivery? If qrunner doesn't modify config.db anymore, could it open config.db read only?
The reason I ask is that, while the current sourceforge.net list server is still doing ok with 16,000+ lists, 600,000 Emails a day or so, and full SMTP callbacks on each incoming message, I'm still getting pressure to load balance the machine, especially for the high availability part :-)
If I can have qrunner not lock ocnfig.db, the only lock contention I'll have is when lists are modified through the web, and even if I share ~mailman over NFS, I'm confident that we won't hit some NFS race condition because the same list is being modified by two different admins at the same exact nanosecond.
So, I'll probably be able to devote time over the next couple months to writing this, but I'm interested in how people feel such a beast should look, especially (4).
I think the NFS approach is the simplest by far :-) It even works today if you don't deliver thousands of messages in a few seconds to the same list :-) (actually with linux 2.4 or some other OS, and mailman 2.1, the bug may not be triggered anymore)
Marc
Microsoft is to operating systems & security .... .... what McDonalds is to gourmet cooking
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