RAID 0 + 1 is a mirror of stripes and is used for both replicating and sharing data among disks. This configuration combines the most popular of the multiple RAID levels, RAID 0 and 1 to achieve the best features of striping and mirroring to yield large arrays with high performance in most uses and superior fault tolerance. It provides redundancy by writing all data to four or more disks. RAID 0+1 is considered an excellent solution for sites that need high performance but are not concerned with achieving maximum reliability.
Typically, this array type is used in applications requiring both high performance and reliability and willing to sacrifice capacity to get them. The size of a RAID 0+1 array can be easily calculated, where N is the number of drives (must be even) and C is the capacity of the smallest drive in the array: Size = ( N x C ) ÷ 2.
Common Uses Of RAID 0+1
- Mid-size databases
- Fileservers
- Imaging applications
Common nested raid failure reasons
- Single or multiple drive damage
- Intermittent disk failure resulting in configuration corruption
- RAID controller failure
- Server registry configuration lost
- Accidental reconfiguration of RAID volumes
- Accidental replacement of media components
- Other reasons not associated with the member disks (operator error or card failure)
What To Do When RAID Fails
- If a drive is making unusual mechanical noises, turn it off immediately and contact a data recovery specialist
- Do not replace a failed drive with a drive that was part of a another RAID system
- Zero out disk replacement drive before use
- Label the drives with their position in a RAID array
- Do not run volume repair utilities or defragmenter utilities on suspected bad drives
- Contact professional data recovery specialists for a consultation to receive guidance on your particular situation