User Manual

Chapter 8 Storage Manager
Cloud Storage User’s Guide
101
RAID 10
RAI D 10 (RAI D 1+ 0) is a nest ed RAI D where t wo RAI D 1 arrays are stored on the physical disks
wit h a RAI D 0 array on top. I t is a st ripe of m irrors. RAI D 1 provides redundancy while RAI D 0
boost s perform ance. The following figure shows two disks in t wo RAI D 1 arrays. Data is duplicat ed
across t wo disks, so if one disk fails, there is still a copy of the dat a. These t wo arrays are
configured as a single RAI D 0 array for fast er perform ance.
Typical applicat ions for RAI D 10 are those requiring bot h high perform ance and reliability such as
ent erprise servers and high- end m oderate- sized dat abase syst em s. RAI D 10 is oft en used in place
of RAI D 1 or RAI D 5 by t hose requiring higher perform ance. I t m ay be used inst ead of RAI D 1 for
applications requiring m ore capacity.
RAID 5
RAI D 5 provides the best balance of capacity and perform ance while providing data redundancy. I t
provides redundancy by st riping dat a across t hree disks and keeps t he parit y inform ation ( AP) on
the fourt h disk ( in each stripe) . I n case of disk failure, data can be recovered from t he surviving
disks using the parit y inform ation. When you replace t he failed disk, t he reconstruct ed data is
writt en ont o t he new disk. Re-synchronize t he array t o have it return to its original stat e. The
following exam ple shows dat a st ripped across t hree disks (A1 t o A3 in the first strip for exam ple)
wit h parity inform ation ( AP) on the fourt h disk.
The capacity of a RAI D 5 array is t he sm allest disk in t he RAI D set m ult iplied by one less t han the
num ber of disks in t he RAI D set. For exam ple, if you have four disks of sizes 150 GB, 150 GB, 200
Table 35 RAI D 10
RAID 0
RAID 1 RAID 1
A1 A1 A2 A2
A3 A3 A4 A4
A5 A5 A6 A6
A7 A7 A8 A8
DISK 1 DISK 2 DISK 3 DISK 4
Table 36 RAI D 5
A1 A2 A3 AP
B1 B2 BP B3
C1 CP C2 C3
DP D1 D2 D3
DISK 1 DISK 2 DISK 3 DISK 4