Hi Peter, On Sat, Aug 27, 2022 at 10:00:32PM -0400, Peter Sanders wrote: > After the hardware was replaced, my array will not assemble - mdadm > assemble reports no RAID superblock on the devices. > root@superior:/etc/mdadm# mdadm --assemble --scan --verbose > mdadm: looking for devices for /dev/md/0 > mdadm: cannot open device /dev/sr0: No medium found > mdadm: No super block found on /dev/sda (Expected magic a92b4efc, got 00000000) > mdadm: no RAID superblock on /dev/sda > mdadm: No super block found on /dev/sdb (Expected magic a92b4efc, got 00000000) > mdadm: no RAID superblock on /dev/sdb I'm wondering if this is one of those motherboards that at boot helpfully writes a new empty GPT on any drive that it thinks doesn't have any kind of partitioning. I say this because: - It looks like you're using sd{a,b} etc with no partitions - I've heard of motherboards that do this - You say you just switched to a new motherboard Cheers, Andy