Hi, On Fri, Jul 01, 2022 at 07:23:18PM +0100, Matthias Scheler wrote: > I'm trying to migrate the mailing lists on my server from legacy Mailan to > Mailman 3 to be able to finally update the system from Buster to Bullseye. > I've found guides how to migrate the configuration and lists but I haven't > found a guide how to complete the basic installation on Debian.
I've just done this in the last couple of weeks in order to move away from Mailman 2, but I did it to a new bullseye host. Some thoughts and experiences: - MM3 is a complex app with the web side being another complex Django app. I personally would not try to install this from packages onto Debian 10. I would go to Debian 11 first, because otherwise you are installing old stuff and guaranteeing more work for the near future. If anything is wrong you will probably be told to use a more up to date version. I doubt Debian's mm3 maintainers have time to be backporting any non-security bug fixes. In order to move a list from MM2 to MM3 all you need is the config.pck and the mbox archive file. You don't need a running MM2 install. It's easier to install onto a new host but if you are going to do it in place I think I'd take a backup and uninstall MM2 first, upgrade host to bullseye and get everything else sorted, then install MM3 and migrate lists in. - Both mailman3 and mailman3web need a database. The Debian packages default to sqlite just to get something that works. This really isn't suitable for production use so first thing to do is install mariadb or postgres. Don't delay or you'll just have to redo your work. - Debian packages use Whoosh for full text indexing. I am struggling with this right now as reindexing it all (which by default mailman3web does once per month, and you'll do after importing a list archive) takes many many hours and uses lots of memory. I had around 200k messages in my archives and it took well over 24 hours at ~4G memory usage to initially index these messages. I just hit the monthly reindex job and I had to kill it after 2 days at 100% CPU and 4G memory use. I got rid of archives that were never looked at and this reduced my message count to ~6k. The monthly job for this has been running for 119 minutes so far. I've been advised to switch to Xapian instead of Whoosh. - The documentation in /usr/share/doc/mailman3-web/README.Debian.gz and /usr/share/doc/mailman3/README.Debian is good and should be read. - By default uWSGI will be used to connect web server (e.g. Apache or nginx) to mailman. I and at least one other person are currently seeing a slow memory leak in uWSGI: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1014037 Upstream Mailman3 project have recommended gunicorn instead. I haven't yet looked into this. - The default templates for messages that will be automatically sent, e.g. subscription welcome, confirm subscribe, admin notice about pending moderation decisions, etc., only invite people to use email to interact with Mailman. i.e. they don't have web links in them, unlike with Mailman 2. This is because, unlike Mailman 2, Mailman 3 can't assume how your web interface works or even if you have one at all. If you have any even slightly non-technical users they will probably want web links, particularly if they have grown used to how Mailman 2 worked. You can override the default templates for your entire site by creating directory /var/lib/mailman3/templates/site/en/ and then putting files like "list:user:action:subscribe.txt" in it. The "en" is the language code, so use a different two-letter code if yours isn't English. The default content of these templates can be seen at: https://gitlab.com/mailman/mailman/-/tree/master/src/mailman/templates/en You can also use list/<xx>/ directory for per-list overrides. Tags that you can use in templates: https://docs.mailman3.org/projects/mailman/en/latest/src/mailman/rest/docs/templates.html#templated-texts I hope some of that helped. Cheers, Andy -- https://bitfolk.com/ -- No-nonsense VPS hosting