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 to four drive failures while maintaining data integrity if each

 

failed disk is in a different RAID 3 array.

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 15

 

The initiator takes one ID per channel. This leaves 15 IDs

 

available for one channel.

Chapter 3 RAID Levels

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