SCF Reference Manual for the Storage Subsystem (G06.27+, H06.04+)

Disk Load Balancing
SCF Reference Manual for the Storage Subsystem—529937-008
8-14
Establishing a Disk Load Balance in RVUs Prior to
G06.11
This process affects all disk processes that use these SACs.
Establishing a Disk Load Balance in RVUs Prior to G06.11
In RVUs prior to G06.11, you can simplify disk load balancing if you first establish a
starting point for SAC ownership so you know the owner of all SACs.
You enforce SAC ownership by using the PRIMARY DISK, FORCED command, which
produces this behavior:
•
A specified disk primary process must run in the specified processor.
•
All SACs that are used to access the disk become owned by that processor.
•
All disk processes using those SACs must use that processor.
1. Force all mirrored disks in the group 02 topology branch to run in processor 2:
-> PRIMARY $D02*, 2, FORCED
2. Change SAC ownership for all group 02 disks to processor 2:
-> INFO DISK $D02*, LABEL
3. Again swap the processors for these same disks, this time to processor 3:
-> PRIMARY $D0201, 3, FORCED
4. Change SAC ownership to processor 3:
-> INFO DISK $D02*-*, LABEL
5. If you want all these disks to run in processor 2, enter one final PRIMARY
command:
-> PRIMARY $D02*, 2, FORCED
6. Change SAC ownership to processor 2:
-> INFO DISK $D02*, LABEL
Note. Loss of SAC ownership is detected only when an I/O is attempted. When ownership of
both SACs is lost, a read from one or both paths detects a loss of ownership. However, a read
from one path whose SAC ownership was not lost would not detect the loss of ownership of the
SAC on the path to the other disk.