RAID 30

 

RAID 30 is a combination of RAID 0 and RAID 3. RAID 30 provides high data transfer speeds

 

and high data reliability. RAID 30 is best implemented on two RAID 3 disk arrays with data

 

striped across both disk arrays. RAID 30 breaks up data into smaller blocks, and then stripes the

 

blocks of data to each RAID 3 raid set. RAID 3 breaks up data into smaller blocks, calculates

 

parity by performing an exclusive-or on the blocks, and then writes the blocks to all but one drive

 

in the array. The parity data created during the exclusive-or is then written to the last drive in each

 

RAID 3 array. The size of each block is determined by the stripe size parameter, which is set

 

during the creation of the RAID set.

 

RAID 30 can sustain one drive failure per RAID 3 array and still maintain data integrity. For

 

example, the RAID 30 configuration in the graphic below has two RAID 3 arrays. It can survive

 

two drive failures, as long as the failed drives are in different RAID 3 arrays.

Uses

Use RAID 30 for sequentially written and read data, pre-

 

press and video on demand that requires a higher degree of

 

fault tolerance and medium to large capacity.

Strong Points

Provides data reliability and high data transfer rates.

Weak Points

Requires 2 – 4 times as many parity drives as RAID 3.

Drives

Six to 32

Chapter 3 RAID Levels

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