Hi,
>> I definitely suggest you make a backup of each device
superblock and
>> distribute it somewhere safe in the unlikely event two devices in a
>> mirrored array stop cooperating. The superblocks do come in handy from
>> time to time when they can't be acquired once problems happen.
>
> Do you have any suggestions on how to do this?
mdadm -E for each device, and point it to a file using >> - for the
purposes of the backup you could write all devices to one file, it's
up to you.
Ah, I thought you were referring to actually storing information from
the disk itself, such as the bootsector or MBR, not just a list of the
partition info.
There's also a great resource on recovering a failed array here:
https://raid.wiki.kernel.org/index.php/RAID_Recovery
Thanks,
Alex