Okay, ordered an SK Hynix SC311 128GB 2.5" SATA SSD for the replacement board.

This actually delays the migration by about a week. It may also need a firmware update - specifically, a may not occasionally boot scenario.

I also had an idea: relocating the database to another drive... again. I did this last time and it was a success, but it was with 2x 80GB IDE drives as a dm-integrity RAID 1 test.

The database is on the same drive setup as the rest of the webserver data... which is not the system drive.