RAID

RAID 0

Striping.

RAID 1

Mirroring.

RAID 5

Striping w/ one parity drive.

RAID 6

Striping w/ two parity drives.

Nested RAID is aka…

RAID 1 +0 or RAID 10

Nested RAID (10)

A stripe of mirrors.

RAID 0: Striping

File blocks split into two or more physical drives.

Raid 0: Striping

Known for it’s speed. Data written quickly.

RAID 0: Striping

No redundancy. If one drive fails you lost access to all data.

RAID 1: Mirroring

File blocks duplicated between two or more physical drives.

RAID 1: Mirroring

Exact duplicate of whatever’s on Disk 0 on Disk 1.

RAID 1 : Mirroring

We need twice as much storage space to maintain redundancy.

RAID 1: Mirroring

Drive availability isn’t affected if one drive fails.

RAID 5: Striping w/ Parity

Striping just like RAID 0 but the last drive gets parity of info stored instead of a piece of the file.

Striping

Divides data up into equal parts and spreading it across multiple drives to improve performance.

Parity

Can be used to identify and correct errors.

RAID 5

Efficiently uses disk space.

RAID 5

Has high redundancy. Data is available after drive failure.

RAID 5

Parity calculation may affect performance in recovery mode.

RAID 6: Striping w/ 2x parity

Could lose two drives and data would still be available.

RAID 6: Striping w/ 2x parity

Adds another parity block and requires at least four drives.

RAID 10

Has the speed of striping and redundancy of mirroring. A stripe of mirrors best of both worlds.

RAID 10 still has…

Zero redundancy.

RAID 10

Needs at least 4 drives and we could lose multiple drives and still be fine.