SCF Reference Manual for the Storage Subsystem (G06.24+, H06.03+)

SCF Reference Manual for the Storage Subsystem—529937-007
8-1
8 Disk Load Balancing
Disk load balancing seeks to distribute the disk work load across all fabrics and
processors in the system. This subsection describes load balancing between the X and
Y fabrics and pairs of processors in a NonStop S-series processor enclosure. A
processor enclosure and its I/O enclosures are called a topology branch.
The principles that apply to the internal disks in these examples also apply to 45xx
disks in a modular disk subsystem.
Using reports from products like Guardian Performance Analyzer and Measure, you
can assign each disk in a topology branch to run its primary processes in a specific
processor. For more information, see the GPA Manual and Measure User’s Guide.
Disk Load Balancing Between Fabrics
Because a storage adapter in a NonStop S-series server is permanently assigned to a
fabric (adapters in slots 50, 51, and 53 use the X fabric; adapters in slots 52, 54, and
55 use the Y fabric), you can examine a detailed STATUS ADAPTER report to see
whether the mirrored disks on an storage adapter are balanced between the X and Y
fabrics.
1. Examine this display:
-> STATUS ADAPTER $ZZSTO.#*.GRP-3*, DETAIL
The disks are balanced if the primary (-P or -B) disk or the mirror (-M or -MB) disk
has an asterisk.
Topic Page
Disk Load Balancing Between Fabrics
8-1
Disk Load Balancing Between Processors
8-2
Guidelines for All G-Series RVUs
8-3
Guidelines for G06.11 and Later RVUs
8-3
Disk Load Balancing on G06.10 and Earlier RVUs 8-6
Understanding SAC Ownership
8-6
Guidelines for G06.10 and Earlier RVUs 8-6
PRIMARY Command Function in G06.00 Through G06.10 8-8
PRIMARY Command Function in G05.00 and Earlier 8-11
Establishing a Disk Load Balance in RVUs Prior to G06.11 8-14
Maintaining a Disk Load Balance 8-18