RAID and Enterprise Storage

Redundant Array of Independent Disks (RAID) is a storage technology that creates a data loss fail-safe by merging two or more hard disk drives (HDDs) or solid-state drives (SSDs) into one cohesive storage unit, or array.

RAID mode	Description	Operation	Advantages	Disadvantages	Recovery
RAID 0	Striped disks	Data is split evenly between two or more disks.	Large size and the fastest speed.	No redundancy.	If one or more drives fails, this results in array failure.
RAID 1	Mirrored disks	Two or more drives have identical data on them.	A single drive failure will not result in data loss.	Speed and size is limited by the slowest and smallest disk.	Only one drive is needed for recovery.
RAID 3	Striped set with dedicated parity	Data is split evenly between two or more disks, plus a dedicated drive for parity storage.	High speeds for sequential read/write operations.	Poor performance for multiple simultaneous instructions.	A single drive failure will rebuild.
RAID 5	Striped disks with distributed parity	Data is split evenly between three or more disks. Parity is split between disks.	Large size, fast speed, and redundancy.	The total array size is reduced by parity.	A single drive failure will rebuild.
RAID 10	1+0; Striped set of Mirrored Subset	Four or more drives are made into two mirrors that are striped.	Larger size and higher speed than RAID-1, and more redundancy than RAID-0.	No parity.	Only one drive in a mirrored set can fail.
JBOD	Just a Bunch Of Disks	Any number of drives are accessed independently by the operating system.	Software RAID modes can be used.	Hardware RAID may have better performance.	N/A