SCF Reference Manual for the Storage Subsystem (G06.28+, H06.05+, J06.03+)

For detailed guidelines about how to use the PRIMARY command, see “Swapping Processors
for a Disk” (page 109).
The disk processing load within each enclosure should be evenly balanced between the processor
pair in that enclosure. Assuming that each disk handles the same processing load, each enclosure
should have one processor managing half of the primary disk processes and the other processor
managing the other half. If one disk has to support a heavier processing load, you need to primary
fewer disks from that processor.
Topology Branch Example for G06.11 and Later RVUs
The group 02 topology branch includes processors 2 and 3 in the group 02 processor enclosure
and the three I/O enclosures attached to it (groups 21, 22, and 23). In the figure below, the disk
processes are configured as follows:
• Processors 2 and 3 jointly own all SACS in the same topology branch (groups 02, 21, 22,
and 23).
• Processor 2 manages the primary disk processes using the shaded SACs and disks.
• Processor 3 manages the primary disk processes using the white SACs and disks.
• For simplicity, four disks are shown connected to each communication bus. The enclosure can
have up to eight disks per bus (16 disks in each enclosure).
120 Disk Load Balancing