Albeit late, here is the notice of this afternoon's maintenance that took waaaaaaaaaaay longer than it should have.
We've been considering upgrading the forum box hardware for a while, which should be very easy as it's just a matter of moving the disks to another machine.
Unfortunately a lot of problems were encountered when attempting to do that on Scaleway's platform, turning a 10 minutes matter into an almost 5 hours long fight against buggy boot scripts and discovering new issues with their platform along the way.
In order to minimize downtime, the old box is running on slightly upgraded hardware but still with the disk that takes an hour to boot whenever we need to perform a maintenance that requires taking down the box (to make backups for instance).
The new box works much better (boots completely under 5 minutes instead of almost an hour) but requires the OS disk to be fully recreated. So instead of causing an insanely long downtime, the new OS disk will be prepared over time and once ready the current data drive will be moved over. I have tested it and it works as expected.