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Multi-level RAID 1+0 combines the redundancy of RAID 1 with the performance enhancements of RAID 0. A RAID 1+0 array is constructed by taking two or more RAID 1 Sub-Arrays and applying RAID 0 striping across these arrays to create a RAID 0 Super-Array. RAID 1+0 is often referred to as a stripe of mirrors because it operates by striping data across multiple mirrored sets. Some people might refer to this configuration as a RAID 0+1 but this does not follow most industry standards. The standard multi-level RAID naming convention is to list the Sub-Array first and the Super-Array second. The following chart illustrates a RAID 1+0 setup for an array of six disks. To see the difference between RAID 1+0 and RAID 0+1, see our RAID 0+1 page .

RAID 1 Sub-Arrays (mirrors)
RAID 0 Super-Array (stripes)	Disk 1	Disk 2	Sub-Array A
	Disk 3	Disk 4	Sub-Array B
	Disk 5	Disk 6	Sub-Array c

When data is inserted into a RAID 1+0 array, it is first split into stripes and each stripe is written to one disk of each RAID 1 Sub-Array. The stripes are then mirrored individually to the other disk in the Sub-Array. If any disk from a RAID 1 Sub-Array fails, the system will continue to operate normally since the Sub-Arrays are redundant. The system will even continue to operate normally if a single disk from each Sub-Array fails. When a disk failure occurs in a RAID 1+0 system, the system is reduced to a state in between RAID 0 and RAID 1. For example, if disk 4 fails, the system has redundant copies of the stripes from disks 1 and 5 but not from disk 3.

See our RAID 0 recovery page for a detailed explanation. Gillware looks forward to helping you with your multi-level RAID 1+0 reconstruction needs. To place an order please call our 800 number.

Continue reading about RAID Arrays at one of our informational pages listed below.