[Mailman-Users] Synchronizing Mailman between two servers.
ifetch at du.edu
Thu Sep 22 19:46:40 CEST 2005
i'm looking at this for our setup as well. How are others handling
the Mailman processes (qrunners) starting on a second server once the first
server has gone down, and switching back to the first server once it has
Mailman's locks are usually not cleaned up properly when a server
unexpectedly fails - although we could force the locks to be removed and
start mailman processes on the second machine, we'll need to be sure that
the first machine is really "dead". I assume two machines trying to run
qrunners on the same mailman directories at once is not a good thing.
This brings me to search for a way to insure that even if other
services on a machine are not available, Mailman is certainly not
operating on the Mailman directories before I try starting Mailman
processes on a second machine. Perhaps looking at access /
modification times of particualr files or directories, relative to the
current time? Are there any ideas or comments from others doing or
looking into this?
- Ivan Fetch.
>> I'm very interested in the solution you chose, and in how well it works
>> for you.
> Sorry, I missed the original message.
>> I'm in the process of designing a fault-tolerant mailman installation,
>> and any wisdom from experience would be very useful.
> Generally speaking, I don't think that many people try to do
> this. You can off-load the web processing with multiple front-end
> web proxies, and you can off-load the mail processing with multiple
> inbound and outbound mail servers (usually best kept as separate
> groups, since the anti-spam, anti-virus, and certain other
> requirements are different for inbound versus outbound use), and the
> rest is just Mailman itself.
> But, if you do want to go the whole nine yards, the Mailman
> programmers have been pretty careful to keep everything relatively
> NFS-safe, so you should just be able to have an NFS filesystem which
> is then mounted on all of the Mailman servers (preferably served by a
> high availability/redundant NFS server cluster). Doing things over
> NFS will slow down individual operations, but the overall aggregate
> throughput might be able to be higher, if the NFS server has the
> right architecture and you spread the load out across enough Mailman
> servers, etc....
>>> Any thoughts on what is the best way to synchronize mailman databases
>>> between to linux boxes?
> Mailman doesn't really use databases. At least, not
> out-of-the-box. There are third-party unsupported patches to allow
> database member adapters, but that's about it.
> Mailman stores pretty much everything into Python "pickle" files,
> which is a particular binary Python-specific file format that can be
> quickly saved and re-loaded in the native binary format.
>>> If my alias_maps are defined the same in /etc/postfix/main.cf are the
>>> same on both hosts can I just duplicate my /usr/lib/mailman and
>>> /var/lib/mailman directories?
> Duplicate? What do you mean by "duplicate"? Just once? If so,
> then the directories would get out-of-sync. You'd have to keep all
> the directories in sync somehow.
> In a nearline backup method, something as simple as rsync would
> suffice, and would potentially only lose any information that was
> written since the last rsync.
> In a production OLTP type of environment, you'd have to use
> shared filesystems between the sets of machines, and you'd have to
> make sure that those shared filesystems implement all the necessary
> cluster-wide locking facilities, etc... to keep Mailman working
> Brad Knowles, <brad at stop.mail-abuse.org>
> "Those who would give up essential Liberty, to purchase a little
> temporary Safety, deserve neither Liberty nor Safety."
> -- Benjamin Franklin (1706-1790), reply of the Pennsylvania
> Assembly to the Governor, November 11, 1755
> SAGE member since 1995. See <http://www.sage.org/> for more info.
> Mailman-Users mailing list
> Mailman-Users at python.org
> Mailman FAQ: http://www.python.org/cgi-bin/faqw-mm.py
> Searchable Archives: http://www.mail-archive.com/mailman-users%40python.org/
> Unsubscribe: http://mail.python.org/mailman/options/mailman-users/ifetch%40du.edu
> Security Policy: http://www.python.org/cgi-bin/faqw-mm.py?req=show&file=faq01.027.htp
More information about the Mailman-Users