Often written RAIDⁿ, or RAIDn, it is an alternative to traditional RAID that solves the problem of more than one disk drive failing within the recovery time window.

All traditional RAID configurations will fail to recover if more than one disk fails within the recovery time window. The recovery time window is the time it takes to replace the failed drive and then rebuild the data on that drive from the redundant drives.

The larger a single drive is, the longer it takes to recover its data from the redundant data on the non-failing drives, and the higher the odds that a second drive will fail during this time period. Also, the time it takes to alert a technician and have him or her replace the failed drive is part of this window.

Sometimes an extra hot-spare is included in the array which is used to automatically replace any single disk that fails. This, of course, reduces the storage efficiency of any configuration it is used with but increases fault tolerance by reducing the duration of the recovery window.

RAIDⁿ solves this problem by allowing installers to specify the number of disks that can fail simultaneously without loss of data.


The down-side of RAIDn is that it is proprietary.