On Tue, Apr 14, 2026 at 1:08 PM Prasanth Nair <prasanth.nair@linaro.org> wrote:
Hi Odhiambo and Stephen,
Thank you both for your helpful responses and guidance.
Given that this is a critical production system, I am now considering migrating to a new server using a host-based Mailman installation first, before evaluating a Docker-based setup at a later stage.
In that case, could you please advise on the recommended approach for migrating from my current host-based Mailman 3 installation to a new host-based server? In particular, I would appreciate any guidance on:
Safely migrating the PostgreSQL databases (e.g., dump and restore approach)
Preserving mailing lists, memberships, and configurations
Migrating HyperKitty archives and Postorius data
Any best practices to ensure a smooth cutover with minimal downtime
Any documentation or pointers you can share would be greatly appreciated.
For a host-based installation, the recommended method is documented here: https://docs.mailman3.org/en/latest/install/virtualenv.html
If your current installation is based on the above, then (off the top of my head):
- Ensure that the database backend on the new host meets the specified requirements in the above documentation.
- Ensure that the Python version is the same on both hosts (so that nothing bites you immediately to migrate). @Stephen J. Turnbull <steve@turnbull.jp> call them software gremlins :-)
- Install MM3 the normal way on the destination host and ensure you run all the tests. 'mailman info' should show similar details on both hosts.
- Postfix should be configured the same way on both hosts. The migration will involve the following: (a) dumping the DB on the source and restoring on the destination (b) zip up /etc/mailman3 on the source and extract it on the destination (c) zip up /opt/mailman, move it to the destination server, extract it and copy the files/directories (except the venv directory) from this archive to /opt/mailman/ You then fix the permissions so that /opt/mailman is owned by the mailman user. The commands are on the link liven above (d) You need your Nginx vhost configs to be migrated to the new server. (e) DNS. Oh DNS! You will flip the records to point to the new server
That should preserve everything as you want.
These details are off the top of my head. I might have forgotten something so I beg your pardon in advance.
-- Best regards, Odhiambo WASHINGTON, Nairobi,KE +254 7 3200 0004/+254 7 2274 3223 In an Internet failure case, the #1 suspect is a constant: DNS. "Oh, the cruft.", egrep -v '^$|^.*#' ¯\_(ツ)_/¯ :-) [How to ask smart questions: http://www.catb.org/~esr/faqs/smart-questions.html]