Physical Disks - Dell PowerEdge RAID H700 User Manual

The parity data is distributed across all the physical disks in the system. If a
single physical disk fails, it can be rebuilt from the parity and the data on the
remaining physical disks. RAID level 5 combines distributed parity with disk
striping, as shown in Figure 2-3. Parity provides redundancy for one physical
disk failure without duplicating the contents of entire physical disks.
RAID 6 combines dual distributed parity with disk striping. This level of
parity allows for two disk failures without duplicating the contents of entire

physical disks.

Figure 2-3. Example of Distributed Parity (RAID 5)
Stripe element 1 Stripe element 2
Stripe element 7 Stripe element 8
Stripe element 13
Stripe element 14
Stripe element 19 Stripe element 20
Stripe element 25
Parity (26–30) Stripe element 26
NOTE:
Parity is distributed across multiple physical disks in the disk group.
Figure 2-4. Example of Dual Distributed Parity (RAID 6)
Stripe element 1 Stripe element 2
Stripe element 5 Stripe element 6
Parity (9–12)
Stripe element 13 Stripe element 14
NOTE:
Parity is distributed across all disks in the array.
20
Overview
Stripe element 3
Stripe element 9
Stripe element 15
Parity (16–20)
Stripe element 21
Parity (21–25)
Stripe element 27
Stripe element 3
Parity (5–8)
Parity (9–12)
Stripe element 9
Parity (13–16)
Stripe element 4 Stripe element 5
Stripe element 10 Parity (6–10)
Stripe element 11
Parity (11–15)
Stripe element 16 Stripe element 17
Stripe element 22 Stripe element 23
Stripe element 28
Stripe element 29
Stripe element 4 Parity (1–4)
Parity (5–8) Stripe element 7
Stripe element 11
Stripe element 10
Parity (13–16) Stripe element 15
Parity (1–5)
Stripe element 6
Stripe element 12
Stripe element 18
Stripe element 24
Stripe element 30
Parity (1–4)
Stripe element 8
Stripe element 12
Stripe element 16