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

Disk Load Balancing
SCF Reference Manual for the Storage Subsystem—529937-007
8-8
A Closer Look at Eight Disks
A Closer Look at Eight Disks
Looking more closely at the disks in the group 03 processor cabinet, this configuration
is the ideal situation for G06.10 and earlier RVUs:
•
All primary disk processes run in processor 4.
•
All backup disk processes, represented with a prime mark (') run in processor 5.
•
Processor 4 owns all four SACs.
PRIMARY Command Function in G06.00 Through G06.10
On G05.00 through G06.10, the PRIMARY command changes processor ownership of
active paths. (The FORCED option forces all SACs to change ownership.) This
change in ownership in turn causes other IOPs in the same topology branch to perform
additional path switches or processor swaps to recover from the loss of SAC
ownership.
-M
-P
-P
-P -P
-P-M
-M
Processor 4
X Y
SCSI Bus 2
SAC 1
SCSI Bus 1
SAC 1
SAC 2
SAC 2
$D0303-P
$D0301-P
$D0307-P
$D0305-P
Processor 5
X Y
X Y
-B -B -B -B
$D0301
$D0303
$D0305
$D0307
$D0308
VST503.vsd
$D0301’
$D0303'
$D0305’
$D0307’
$D0308’
-B
-MB
-MB -MB
$D0301-M
$D0303-M
$D0308-P
$D0305-M