[wplug] linux software raid

[Patrick Wagstrom]

> I have a server running software raid5 on 4 250GB drives (3 data + 1 
> parity).  The drives in this machine are all on PCI IDE controllers, so I
> have a spare IDE controller on the motherboard.
> 
> I'd like to add a spare drive to the array and connect it via the 
> motherboard controller.  But if the spare gets consumed by a drive failure
> in the array, I'd like to move the spare to the other controllers (where
> the dead drive formerly lived) so that it can participate in the array
> with the same hardware as the others (I don't really know how "good" the
> onboard controller would be, but it ought to be fine for this purpose).
> 
> Will Linux raid tolerate that?  E.g., the spare drive would probably 
> change its name from /dev/hdb to /dev/hdk (or something similar). Would
> the array just figure that out and put me back in business?

If you use mdadm for making a software raid, this should work without any difficulty.  That style of raid puts UUID labels on the drives and organizes the raid based on the UUID.  I've got a 4x320GB raid 5 at home and before I came up with the genius idea of putting a sticker on each drive, they never got plugged back in in the same way they were before I took the system apart.

--Patrick