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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.
Six to 32
Drives
Chapter 3 RAID Levels
23
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