What will happen? Linux software raid autodetecting on an old array...

[Les Mikesell]

Matthew Miller wrote:
> Okay, so, here's the situation. Motherboard on my old computer (a Shuttle)
> went out. Decided to get a new computer, because hey, it was four years old.
> 
> New computer came with two new SATA drives, which I've set up to to be
> mirrored with software raid -- partitions /dev/md0 and /dev/md1.
> 
> All is good.
> 
> Now, had the exact same disk configuration in my old system. If plug in
> those disks into the 3rd and 4th SATA ports, and boot, what will happen?
> 
> I hope the RAID autodetect system is smart enough to not get the old
> /dev/md{0,1} mixed up with the new one and eat data. Right?
> 
> What Will Happen?

I think it will pick one of each of the mdN devices and ignore the 
other.  It won't eat data unless the mismatched disks have matching 
UUIDs which is unlikely unless you image-copied them or had synced with 
the other set in the past.  If you want it to ignore the new set until 
you reconfigure it, fdisk the partition types to something other than FD 
so it won't autodetect at boot up.

-- 

   Les Mikesell
    lesmikesell at gmail.com