Chapter 2
RAID Overview
20
Table 2-2. RAID Level Summary for Spanned Arrays
RAID Level
RAID 10
RAID 50
Also Known As
striping with
mirrored arrays
striping with
distributed parity
Fault Tolerance
yes
yes
Redundancy Type
duplicate
parity
Hot Spare Option
yes
yes
Disks Required:
spans 2 arrays
spans 3 arrays
spans 4 arrays
spans 5 arrays
spans 6 arrays
spans 7 arrays
spans 8 arrays
4
6
8
10
12
14*
16*
6, 8, 10, 12, 14*, 16*, 18*, 20*, 22*,
24*
9, 12, 15*, 18*, 21*, or 24*
12, 16*, 20*, or 24
*
15* or 20*
18* or 24*
21*
24*
Usable Capacity
least
intermediate
Capacity Reduction
50%
capacity of one disk for each array
spanned
Read Performance
intermediate
fast
Random Write
Performance
intermediate
slow
Sequential Write
Performance
intermediate
slowest
Typical Usage
Mostly small
random writes
with fault
tolerance and
enhanced speed
Mostly small, random transfers with
fault tolerance and enhanced speed
*HP NetRAID-2M only. The 1M can only support up to 12 disks per adapter while the
2M can support up to 24 disks per adapter, using external disk enclosures.
