Stripe Unit size: This parameter should be chosen such that the stripe unit size is close to the size of the system I/O requests. The default is set to 8KB.
Note: Once data is stored in the logical drive, the stripe unit cannot be changed without destroying data in the logical drives.
Rebuild Priority: This parameter sets the priority of the execution order of the rebuild I/O requests with respect to the system I/O requests. The rebuild priority can be changed without affecting data in the logical drive.
Parity placement: Parity placement defines how parity is placed in the disk array with respect to the data. The following figure shows the differences between Left Symmetric and Right Asymmetric parity placement.
AAA, BBB, CCC and so on are the data stripe units;
Right Asymmetric (RA)
Disk Disk Disk Disk
1 2 3 4
PP0 AAA BBB CCC
DDDPP1 EEE FFF GGG HHH PP2 III JJJ KKK LLL PP3
Left Symmetric (LS)
Disk Disk Disk Disk
1 2 3 4
AAABBB CCC PP0 EEE FFF PP1 DDD III PP2 GGG HHH PP3 JJJ KKK LLL
The default value is Right Asymmetric. In some situations, you may want to try Left Symmetric to improve performance.
Note: Once a parity placement scheme is chosen and data is stored in the logical drives, it cannot be changed without destroying data in the logical drives.
When
Note: The
3.5.3 Defining a Hot-Spare Disk
After selecting Create/delete array from the main menu of the IBM RAID
Configuration program, the following screen appears:
