RAID 1+0 | Mirrored Sets in a Striped Set 

RAID Level 1+0

RAID Level 1+0 - (2 Drive Minimum (though 4 are more commonly used) - Redundancy Through Mirroring) Mirrored Sets in a Striped Set:  Fault tolerance and increased performance.  This RAID level is a combination of RAID 1 (mirroring) and RAID 0 (striping).  RAID 1+0 can sustain multiple drive failures as long as no mirror loses all of its drives.