So we powered it down for a move, and on power up the RAID configuration has disappeared. The disks, controllers, etc all look OK, just no RAID so no boot.
The suggestion is that it's possible to rebuild the RAID configuration without losing data. Any ideas how? [It seems to be RAID-1 btw]
The RAID is ServerRAID-C100 by LSI. Can see all ths disks on pre-boot, but all . What to do?
Running Windows Server, if it matters.
Shortly after this we used the BIOS to reenter a best guess RAID configuration and it just worked. The system booted, Windows re-appeared and it was as if nothing had ever happened.
In the past year, while still trying to solve the problem permanently, we've repeated this process to recover from power fail some 3 times. This is called living dangerously. We still don't have a good answer why.