Supported RAID Configurations
RAID is short for Redundant Array of Independent (or Inexpensive) Disks, which is a category of storage that employs two or more drives in combination for fault tolerance and performance. There are a number of RAID levels in use today such as 0, 1, 3, 5, 6 and 10. The DXi4700 uses RAID 6.
RAID 6 Configuration
RAID 6 uses block-level striping with two parity blocks distributed across all member disks. Dual parity provided by a RAID 6 configuration ensures that your data retains full integrity even in the event of two hard drive failures. Since single parity RAID levels are vulnerable to data loss until the failed drive is rebuilt: the larger the hard drive, the longer the rebuild will take and the longer the system is vulnerable to possible data loss.
The DXi4700 Node and Expansion modules (JBODs) use RAID 6 volumes for data storage (see Figure 1 , Figure 2, and Figure 3):
- DATA - HDD slots 1–11 (data storage)
- Hot Spare - HDD slot 0
Note: The hot spare drive is initially located in slot 0. If a hard drive is replaced, the replacement drive becomes the new hot spare.
Figure 1: DXi4700 Node RAID Sets
| 1 - HDD Slot 0 | 4 - HDD Slot 3 | 7 - HDD Slot 6 | 10 - HDD Slot 9 |
| 2 - HDD Slot 1 | 5 - HDD Slot 4 | 8 - HDD Slot 7 | 11 - HDD Slot 10 |
| 3 - HDD Slot 2 | 6 - HDD Slot 5 | 9 - HDD Slot 8 | 12 - HDD Slot 11 |
Figure 2: DXi4700 G1 Expansion Module RAID Sets
| 1 - HDD Slot 0 | 4 - HDD Slot 3 | 7 - HDD Slot 6 | 10 - HDD Slot 9 |
| 2 - HDD Slot 1 | 5 - HDD Slot 4 | 8 - HDD Slot 7 | 11 - HDD Slot 10 |
| 3 - HDD Slot 2 | 6 - HDD Slot 5 | 9 - HDD Slot 8 | 12 - HDD Slot 11 |
Figure 3: DXi4700 G2 Expansion Module RAID Sets
| 1 - HDD Slot 0 | 4 - HDD Slot 3 | 7 - HDD Slot 6 | 10 - HDD Slot 9 |
| 2 - HDD Slot 1 | 5 - HDD Slot 4 | 8 - HDD Slot 7 | 11 - HDD Slot 10 |
| 3 - HDD Slot 2 | 6 - HDD Slot 5 | 9 - HDD Slot 8 | 12 - HDD Slot 11 |
