Linux Kernel 6.18.3 had a bug that caused crashes every 2-3 hours followed by a hang.

So having exhausted 6.18.x I tried the pre-release of 6.19-rc3, the developers did not document the fact that it made substantial changes to the RAID super block, but it did. Since all of the storage on this machine is in the form of RAID arrays, this resulted in none of them being assemblable and the machine being unbootable. It said that I needed mdadm-1.45 or later, and 1.45 was the very most recent version.

I drove home, compiled 1.45, wrote to a USB thumb drive and a rescue file system on another USB, drove down, booted off the rescue, installed mdadm 1.45 but it also claimed the superblock was not usable. So much for it needing 1.45, NO version of mdadm worked.

I ended up rebuilding all the raid metadata keeping the file systems, this worked and everything is back up and we are back on 6.17.9 in spite of it not being completely stable it is less crippled than current 6.18 releases or