This is getting really ridiculous, but the server has a failing hard drive again, so it will need replacement. This time, SMART seems to have caught the error before the hard drive crashed for real, but I don't yet know if all sectors are readable on it. I'll try transferring the data from it before asking Hetzner to replace the drive.
For what it's worth, I'm fairly sure that the drive failure has been the cause of the extra lag on top of the usual horrible lag. ^^
As usual, I'll keep the game server down while the data move and drive replacement are under way.
Update 1: I scheduled a replacement with Hetzner at 01:00 UTC, so the whole website will, as usual (as is pleasant to say in the context of hard drive failures ^^), be down for a while around that time.
Update 2: The hard drive has been replaced, and the RAID resync is running. Expect it to take the usual 12 hours or so before I can turn on the game server again.
Update 3: The resync is done, and so the game server is running again. However, the data from the old disk couldn't be saved in the end, so once again, it will take some time before minimaps are available again.