IBM Advanced SerialRAID Adapters SA33-3285-02, User Manual

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If you select Exact, the replacement disk drive is chosen only from hot
spare disk drives whose size exactly matches the size of the failing disk
drive.
Choose Hot Spare only from Preferred Pool
If you select yes for this option, a hot spare disk drive is selected only from
the hot spare pool that contains the failed member disk drive.
If you select no for this option, a hot spare disk drive is selected, if
available, from the hot spare pool that contains the failed member disk
drive. If no hot spare disk drive is available in that pool, a hot spare disk
drive is selected from the default hot spare pool for that SSA loop (Pool A0
or B0). If no hot spare disk drives are available in pool 0, a hot spare disk
drive is selected from any other hot spare pool.
Allow Hot Spare Splits
If you select no for this option, the RAID manager does not attempt to use
hot spare disk drives to replace missing members when a RAID-1 or
RAID-10 array is split exactly in half, and all the primary or secondary
member disk drives of that array are present.
It is recommended that this option be set to no if the RAID-1 or RAID-10
array is configured to protect against the loss of a physical domain.
Allow Page Splits
If you enable page splits, data that is being written to the array is split into
4096-byte pages. The pages are then written in parallel to the member disk
drives of the array. These actions increase the general speed of write
operations to the array, although the pages are written in a random
sequence. If you disable this option, the data is written sequentially, but the
general speed of write operations is decreased. The sequence in which
data is written to the array might be critical to the program that is using the
data, if an error occurs during the write operation.
Initial Rebuild
When a RAID-1 or a RAID-10 array is first created, the data that is
contained in the primary member disk drive of the array is different from
the data that is contained in the secondary disk drive of the array. When
data is written to the array, it is written both to the primary disk drive and to
the secondary disk drive. The data that is on the secondary disk drive is,
therefore, a mirrored copy of the data that is on the primary disk drive.
If, however, you use a program that attempts to read data from the array
before it has written any data to that array, the data that it reads might not
be consistent. The data can be from either the primary disk drive or from
the secondary disk drive, which at this time, are not mirrored copies of
each other. If you use such a program, use the Initial Rebuild option.
If you select no for this option, any data that your program writes to the
array is mirrored. Any data that your program reads from the array,
however, might not be consistent because it might not have been written
previously by this particular program.
Chapter 6. Using the RAID Array Configurator
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