3Ware 9650SE-2LPML User Manual page 154

Chapter 9. Maintaining Units
144
postpone initialization until a scheduled time. (See "Scheduling Background
Tasks" on page 156).
Note:
Units that do not need to be immediately initialized for full performance will
be automatically initialized using background initialization when they are verified for
the first time. (Verification requires that the units have been previously initialized.)
This will not affect the data on the drives, and the units will perform normally,
although performance will be slowed until the initialization and verification are
completed.
Initialization of Different RAID Types
Information about initialization for each of the different RAID types is
described below and summarized in Table 12 on page 145.
Initialization of RAID 0 Units
RAID 0 units do not need to be initialized and cannot be initialized. RAID 0
units are immediately available for use with full performance when created.
Initialization of RAID 5, RAID 6, and RAID 50 Units
RAID 5 units with three or four drives will be automatically initialized the
first time they are verified.
Regardless of the size, all 9000-series RAID 5, RAID 6, and RAID 50 units
are fully fault tolerant upon creation. 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 6, 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. It is okay that 3 or 4 disk RAID 5 units are not
initialized. These RAID types are fully redundant, regardless of whether or
not they are initialized. Similarly, RAID 50 units with a grouping of 3 or 4
disks in a subunit do not need to be initialized. However, RAID 50 with a
grouping of 5 or more disks in a subunit do need to be initialized for full
performance.
3ware Serial ATA RAID Controller User Guide