Dual-Interface/Dual-Processor Configuration
27
In the example diagrammed in Figure 2-1, one group of five disk modules is
bound by storage-control processor A (SP A) and another group of five disk
modules is bound by SP B.
Figure 2-1
Dual-Interface/Dual-Processor Configuration Example
SCSI-2 interface
Yes
I/O operations fail to storage system disk units owned by the
SP attached to the failed interface. System operator can
transfer control of the failed SP’s disk units to the SP on the
surviving interface, shut down the host, power off and on the
storage system, and reboot the host. When convenient, the
Silicon Graphics SSE or other authorized service provider can
replace the interface and the system operator can transfer
control of disk units to the replacement SP.
SCSI-2 cable
Yes
I/O operations fail to storage-system disk units owned by the
SP attached to the failed cable. System operator can transfer
control of these disk units to the other SP, shut down the host,
power off and on the storage system, reboot the host, replace
the cable, and transfer control of disk units to the replacement
SP.
Table 2-3
Error Recovery: Dual Interface/Dual-Processor Configuration
Failing Component
Continue After
Failure?
Recovery
Disk modules
owned by SP B (LUN 1)
Disk modules
owned by SP A
(LUN 0)
CHALLENGE
CHALLENGE RAID
SCSI-2
interface
SCSI-2
interface
SP A
SP B
SCSI-2 bus
SCSI-2 bus