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Initialization of Different RAID Types
Information about initialization for each of the different RAID types is described below, and summarized in Initialization Requirements for Different RAID Configurations,.
Initialization of RAID 0 Units
RAID 0 units do not need to be initialized and are immediately available for use with full performance when created.
Initialization of RAID 5 and RAID 50 Units
Regardless of the size, all 9000-series RAID-5 and 50 arrays are fully fault tolerant upon creation. This is because these configurations use a specialized scheme for writing to the unit, which does not have to be valid to provide fault tolerance.
Performance of RAID 5 units with 5 or more disks, and RAID 50 units with 2 subunits of 5 or 6 disks will improve after the unit has been initialized. For these configurations, initialization begins automatically after you create them. If you create them in the 3BM utility, zeroes are written to all unit members. If you create them through 3DM, RAID 5 parity is calculated and written to disk, keeping any data in the unit intact.
RAID 5 units with 3 or 4 disks do not need to be initialized to have full performance upon creation. Similarly, RAID 50 units with a grouping of 3 or 4 do not need to be initialized, however RAID 50 with a grouping of 6 do need to be initialized for full performance.
Initialization of RAID 1 and RAID 10 Units
RAID 1 and RAID 10 units do not need to be initialized when they are created to be fault tolerant and are immediately available for use with full performance when created.
Initialization of RAID 1, RAID 10 will take place automatically the first time the unit is verified.
Initialization of a RAID 1 unit results in data from one disk (the disk on the lower channel number) being copied to the other disk. In RAID 10 units, data from one half of the unit is copied to the other half.
After the initialization, subsequent verifies to a RAID 1 or 10 unit check for data consistency by comparing the data from one drive (or set of drives) to the other drive (or set of drives).
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