2-Understanding RAID
RAID 3
RAID 3 provides disk striping and complete data fault tolerance though a dedicated parity drive. RAID 3 breaks up data into smaller blocks, calculates parity on the blocks, and then writes the blocks to all but one drive in the array. The parity data created is then written to the last drive in the array. If a single drive fails, data is still available by computing the inverse operation on the data and parity of the contents corresponding strips of the surviving member disk. RAID 3 is best for applications that require very fast large block data transfer rates or long data blocks
Pros: Very good large file transfer performance. Fault tolerant.
Cons: Not well suited for transaction processing or other I/O
RAID 5
RAID 5 is sometimes called striping with parity at byte level. In RAID 5, the parity information is written to all of the drives in the subsystems rather than concentrated on a dedicated parity disk. If one drive in the system fails, the parity information can be used to reconstruct the data from that drive. All drives in the array system can be used to seek operation at the same time, greatly increasing the performance of the RAID system. RAID 5 is the most often implemented RAID algorithm in RAID arrays.
Pros: Very good general transfer performance.
Fault tolerant.
Cons: Can be slower then RAID 3 at large size file transfers
RAID Set
A RAID Set is a group of disks containing one or more volume sets. The MicroNet RAIDBank4 supports as follows:
•Up to three RAID Sets are supported. Please note that multiple RAID Sets on the same disks are not supported.
•From one to five drives can be included in an individual RAID Set.
•A Volume Set must be created either on an existing RAID set or on a group of available individual disks (disks that are not yet a part of a RAID set). If there are
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