----- Original Message ----- From: "Steve Losen" scl@sasha.acc.virginia.edu To: toasters@mathworks.com Sent: Monday, October 09, 2000 5:55 AM Subject: Re: mixing 18GB and 36GB drives
If you have a raid group of 18GB drives, and add a 36GB drive, the 36GB drive becomes the new parity drive. The old 18GB parity drive becomes a data drive, giving you 18GB of space. After that, all 36GB drives you add give you the full 36GB of space.
(Caveat: This is how Netapp's RAID 4 works. With other vendors, YMMV.)
Bruce
Beware that if an 18G drive fails and the only available hot spare is a 36G drive, then only 18G of the 36G spare drive is used and 18G is wasted. This situation is permanent until the volume is destroyed, at least under DOT 5.3.x.
I thought you could, if you wanted to, get a new 18G drive, fail the 36G drive, and replace it with an 18G drive and the software was smart enough to reconstruct. But, I could be wrong, and of course you put yourself at risk and reduced performance during the reconstruction.
Bruce