RAID 10 (mirroring and striping), min 4 hard drives and RAID controller required

What Is RAID?

As it was originally proposed, the acronym RAID stood for Redundant Array of Inexpensive Disks. However, it has since come to be known as Redundant Array of Independent Disks. RAID was originally described in the paper "A Case for Redundant Arrays of Inexpensive Disks (RAID)" written by three University of California Berkeley researchers: David Patterson, Garth Gibson, and Randy Katz. The concept was presented at the 1988 conference of the ACM Special Interest Group on Management of Data (SIGMOD). In the original Berkeley paper there were five RAID levels (1-5). RAID-6 was added later as an enhancement for RAID-5. In time other levels have been implemented by various companies using the concepts described in the original proposal. These include RAID-0 (striping without redundancy), and multilevel RAID (striping across RAID arrays), and others variants.

The Levels of RAID

RAID 10 (Mirroring + Striping)

• RAID 10 is implemented as a striped array whose segments are RAID 1 arrays
• RAID 10 has the same fault tolerance as RAID level 1
• RAID 10 has the same overhead for fault-tolerance as mirroring alone
• High I/O rates are achieved by striping RAID 1 segments
• Under certain circumstances, RAID 10 array can sustain multiple simultaneous drive failures
• Excellent solution for sites that would have otherwise gone with RAID 1 but need some additional performance boost
• Very expensive / High overhead
• All drives must move in parallel to proper track lowering sustained performance
• Very limited scalability at a very high inherent cost
• Database server requiring high performance and fault tolerance