Users Guide

Selecting a RAID controller
The View Current RAID Configuration and Select Controller page displays all supported RAID controllers attached to the
system. Select the RAID controller on which you want to create the virtual disk, and then click Next.
Selecting RAID levels
Select a RAID Level for the virtual disk:
● RAID 0 — Stripes data across the physical disks. RAID 0 does not maintain redundant data. When a physical disk fails in a
RAID 0 virtual disk, there is no method for rebuilding the data. RAID 0 offers good read and write performance with zero
data redundancy.
● RAID 1 — Mirrors or duplicates data from one physical disk to another. If a physical disk fails, data can be rebuilt using the
data from the other side of the mirror. RAID 1 offers good read performance and average write performance with good data
redundancy.
● RAID 5 — Stripes data across the physical disks, and uses parity information to maintain redundant data. If a physical
disk fails, the data can be rebuilt using the parity information. RAID 5 offers good read performance and slower write
performance with good data redundancy.
● RAID 6 — Stripes data across the physical disks, and uses two sets of parity information for additional data redundancy. If
one or two physical disks fail, the data can be rebuilt using the parity information. RAID 6 offers good data redundancy and
read performance but slower write performance.
● RAID 10 — Combines mirrored physical disks with data striping. If a physical disk fails, data can be rebuilt using the mirrored
data. RAID 10 offers good read and write performance with good data redundancy.
● RAID 50 — A dual-level array that uses multiple RAID 5 sets in a single array. A single physical disk failure can occur in
each of the RAID 5 without any loss of data on the entire array. Although the RAID 50 has increased write performance, its
performance decreases, data or program access gets slower, and transfer speeds on the array are affected when a physical
disk fails and reconstruction takes place.
● RAID 60 — Combines the straight block level striping of RAID 0 with the distributed double parity of RAID 6. The system
must have at least eight physical disks to use RAID 60. Failures while a single physical disk is rebuilding in one RAID 60 set do
not lead to data loss. RAID 60 has improved fault tolerance because more than two physical disks on either span must fail for
data loss to occur.
NOTE: Depending on the type of controllers, some RAID levels are not supported.
Minimum disk requirement for different RAID levels
Table 11. RAID level and number of disks
RAID Level Minimum number of Disks
0 1*
1 2
5 3
6 4
10 4
50 6
60 8
* For PERC S140 / S150 RAID controllers, a minimum of two hard-disk drives are required.
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