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// 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
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