Raid 6 - Dell PS4000 Configuration Manual

Disk Drive
(a)
50 100
Qty / Size
(b)
7
- -
(c)
8
- -
(d)
14
- -
16
700 1400
48
- -
(a) Solid State Disk
(b) Legacy PS50E
(c) PS4000E and PS6000E only
(d) Legacy PS70E,PS100E, PS100X, PS200E and PS300E
Table 6: RAID 5 Total Storage Available with Hot Spares (in GB)
2.4.2

RAID 6

RAID6 (striped set with dual distributed parity) combines N disks in an arrangement where each stripe
consists of N-2 disks that contains data blocks and 2 disks that contain parity blocks. Each parity block
generates parity using a different ―view‖ of the data blocks depending on the RAID 6 implementation.
RAID 6 implementations can tolerate up to 2 drive failures per RAID set at the same time without data
loss. RAID 6 is not recommended for workloads consisting mainly of random writes. For EqualLogic
arrays using a RAID 6 policy, Table 7 shows the drive layouts that are enforced based on the number of
drives in each array and the hot spare configuration.
Disk Drives
7
8
14
16
(c)
8 / 8
(a)
48
(a) 48 drive arrays implement multiple RAID 6 sets within a single chassis.
(b) 48 drive arrays cannot implement a no hot-spare RAID policy.
(c) PS60x0 XVS with 8x 100GB SSD and 8x 450GB SAS.
(d) One 450Gb hot spare, 2x 450 Gb parity and 2x 100Gb SSD parity.
Table 7: RAID 6 Drive Layouts
Table 8 shows the amount of raw storage available using the hot spare drive layouts specified in Table
7 above.
Dell EqualLogic Configuration Guide v11.3
(a)
74 146 250
- - 1250
- - 1500
888 - 3000
- 2044 3500
- - -
Hot Spare
6 Data/Parity
1 Hot-spare
7 Data/Parity
1 Hot-spare
13 Data/Parity
1 Hot-spare
15 Data/Parity
1 Hot-spare
13 Data/Parity
1 Hot-spare
47 Data/Parity
1 Hot-spare
300 400 450
- - -
- - -
- 4800 -
4200 5600 6300
- - -
No Hot Spare
7 Data/Parity
8 Data/Parity
14 Data/Parity
16 Data/Parity
(d)
16 Data/Parity
(b)
N/A
500 600 750
- - -
- - -
6000 - -
7000 8400 10500
21000 25200 -
1000 2000
-
-
-
-
-
-
-
14000
42000 84000
10