I'd call myself a tech head but have never tried to do a RAID before. If I am wanting to do a RAID 1 (mirrored) is it possible to use a 250 GB and a 500 GB? I know that doesn't make sense because I would essentially be wasting half of my 500 GB, but for the time being I would like it to be setup like that so when I fill my 250GB I still have a backup of stuff when I get a new 250GB and do a RAID 1 with my 250GB and the new 250GB if something goes wrong I still have a backup. I will then clear off my 500GB and buy another 500GB and setup a RAID with that.
Hope that makes sense. So basically: Can you do a mirrored RAID with non-matching capacity drives?
Depends on the system. Since RAID is controlled at the hardware level, it depends on the specific RAID controller for your drives. A lot of the older controllers required matching drives, not so much for the overall acpacity of the drive, but mainly because matching drives implied matching block and sector sizes (how the data is physically broken up and written to the spinning platters). Different sized drives would require the controller to break up data into different sized blocks and sectors on the fly in real time, thus slowing performance. But as RAID controllers have increased in speed and complexity, some may handle things differently. You'll have to consult your system manuals to find out for sure.
Thanks. I suppose I can just try it out and see if it works. If it does. Good! If not, I will just deal with it until the 250GB fills up, which won't be too long.
If you are running software raid, you could split your larger disk so that one partition is the same size as the smaller disk and mirror those partitions. As for the rest of the larger disk, you could use it as scratch space.
You could also skip the raid thing altogether and simply keep the same data on both disks.