Missing GB's on my 147 GB disks on a PERC 4 RAID controller

[heyjo1]

I have 7 147 gb disks on a powervault 220 which connects to my PE 2550 with with a PERC 4 raid controller. the bios only recognizes approx 138 gb on each disk. is this normal?

at raid 5 i'm only getting approx 828 gb's instead of 882. where did my 54 gigs go ???

 

[jkupski]

HD manufacturers consider a gigabyte to be 1,000,000,000 bytes (i.e. 10^9) and not 1,073,741,824 bytes (or 2^30, which is actually the correct definition--computers are binary, remember?)

Not knowing the actual drive geometry makes the following calculations a guess, but it's close enough for government work:

HD can store ~147,000,000,000 bytes, which the manf. labels as 147GB. Since you have 7 of these in a raid 5, you actually have 6*147,000,000,000 or 882,000,000,000 bytes of storage available. However, since a gigabyte is actually 1,073,741,824 you find that the actualy storage of the array is 821.43GB.

Clear enough?