I have a new Pegasus2 R8 32 TB (8x 4TB Hitachi disks) arriving later this week. It will arrive as a full RAID-5 with capacity of 7x 4TB or some 28 TB.
I want to configure this R8 as follows
5x 4TB RAID-5 Volumes named PEG-1, PEG-2, PEG-3, PEG-4 and PEG-5 spanning 7 disks. I assume each of these Volumes will use 4/7 TB or some 0.571 TB on each of the 7 disks, right ? If this is correct, then the 5 Volumes will be using 2.857 TB on each of the 7 disks, and 2.857 TB on the 8th parity disk, right ?
The above will leave me with 8x1.143 TB or some 9.143 TB, right. Can I therefore use the 9.143 TB for a RAID-0 spanning the 8 disks and name this Volume as PEG-Scratch.
If my arithmetic is correct then...
The 5x RAID-5 Volumes will consume 22.856 TB across the 8 disks.
The PEG-Scratch RAID-0 will consume 9.143 TB
Thus 22.856 + 9.143 = 31.999 TB (this seems to be correct as the raw capicity for the 8x 4TB disks is 32TB)
Please let me know if I can accomplish the above or if not, what are my other options ?
BTW... the reason for configuring 5x 4TB RAID-5 Volumes PEG-1/2/3/4/5 is because we have an eSATA 5-bay enclosure with 5x 4TB disks. Each of these disks will be used to backup PEG-1/2/3/4/5 each day.