observation about AVID ISIS 5000

Hi -
Just setup my first AVID ISIS with lots of assistance, so my opinion
may be full of balogna.

What I just don't get is why AVID creates three "virtual drives" which are three groups of four drives, each with a hot spare (in a 6 bay chassis running Windows Server 2008), and the 16th drive is an additional hot spare. So 32 TB becomes 22TB, and the max bandwidth is 300MB/sec, because of the way it's stripped. Now I understand that this gives some peace of mind in case of catostrophic failure, but RAID6 does exist on most of the host adaptor cards, and they would get such better performance instead of the three groups of 5 each with a hot spare. The host adaptor card in the Win server is an LSI MegaRAID.

Just wondering about your thoughts on this.

Bob Zelin