Dell PS4000 - RAID 50 Implementation Details; Volume Features and Capabilities; Thin Provisioning for Storage Management

Dell EqualLogic Configuration Guide v11.3
12
Disk Drive
Qty / Size
50
(a)
100
(a)
74
146
250
300
400
450
500
600
750
1000
2000
7
(b)
-
-
-
-
750
-
-
-
-
-
-
-
-
8
(c)
-
-
-
-
750
-
-
-
-
-
-
-
-
14
(d)
-
-
444
-
1500
-
2400
-
3000
-
-
-
-
16
350
700
-
1022
1750
2100
2800
3150
3500
4200
5250
7000
-
48
-
-
-
-
-
-
-
-
11500
13800
-
23000
46000
(a) Solid State Disk
(b) Legacy PS50E
(c) PS4000E and PS6000E only
(d) Legacy PS70E,PS100E, PS100X, PS200E, PS300E and PS400E
Table 10: RAID 10 Total Storage Available with Hot Spares (in GB)
2.4.4 RAID 50
RAID 50 (RAID 5 sets in a striped set) is created by first creating two or more RAID 5 sets, and then
striping data over those RAID5 sets. RAID 50 implementations can tolerate a single drive failure per
RAID5 set.
For EqualLogic arrays using a RAID 50 policy, Table 11 shows the drive layouts that are enforced based
on the number of drives in each array and the hot spare configuration.
Disk
Drives
Hot Spare
No Hot Spare
7
6 Data/Parity
1 Hot-spare
N/A
(a)
8
6 Data/Parity
2 Hot-spares
8 Data/Parity
14
12 Data/Parity
2 Hot-spares
14 Data/Parity
16
14 Data/Parity
2 Hot-spares
16 Data/Parity
48
(b)
46 Data/Parity
2 Hot-spares
N/A
(c)
(a) RAID 50 requires an even number of disk drives. A 7 drive configuration without hot-spare
would result in odd number of disk drives.
(b) 48 drive arrays implement stripes across multiple RAID 5 sets within a single chassis.
(c) 48 drive arrays cannot implement a no hot-spare policy.
Table 11: RAID 50 Drive Layouts
For EqualLogic arrays using a RAID 50 policy, the total quantity of raw storage available can be
computed based on number of drives and the hot spare configuration. The Table 12 below shows the
amount of raw storage available using the hot spare drive layouts specified in Table 11 above.