NonStop NS-Series Planning Guide (H06.03+)

System Configurations
HP Integrity NonStop NS-Series Planning Guide—529567-004
4-22
Fibre Channel Device Configuration Restrictions
Fibre Channel Device Configuration Restrictions
To prevent creating configurations that are not fault-tolerant or do not promote high
availability, these restrictions exist and are invoked by SCF:
•
Primary and mirror disk drives cannot connect to the same Fibre Channel loop.
Loss of the Fibre Channel loop makes not only the primary volume inaccessible
but also the mirrored volume. This configuration inhibits fault-tolerance.
Disk drives in different disk drive enclosures on a daisy-chain connect to the same
Fibre Channel loop.
•
The primary path and backup Fibre Channel communication links to a disk drive
should not connect to FCSAs in the same module of an IOAM enclosure. Τhis
configuration compromises high availability. In a fully populated system, loss of one
FCSA can cause up to 56 inaccessible disk drives on a single Fibre Channel
communications path. This configuration is allowed only, but only if you override an
SCF warning message.
•
The mirror path and mirror backup Fibre Channel communication links to a disk
drive should not connect to FCSAs in the same module of an IOAM enclosure.
Τhis configuration compromises high availability. In a fully populated system, loss
of one FCSA can cause up to 56 inaccessible disk drives on a single Fibre
Channel communications path. This configuration is allowed only, but only if you
override an SCF warning message.
Fibre Channel Device Configuration Recommendations
These recommendations apply to FCSA and disk drive enclosure configurations:
•
Primary disk drive enclosure connects to the FCSA FSAC 1.
•
Mirror disk drive enclosure connects to the FCSA FSAC 2.
•
FCAL port A1 is the incoming port from an FCSA or from another disk drive
enclosure.
•
FCAL port A2 is outbound port to another disk drive enclosure.
•
FCAL port B2 is the incoming port from FCSA or from disk drive enclosure.
•
FCAL port B1 is the outbound port to another disk drive enclosure
•
In a daisy-chain configuration, the ID expander harness determines the enclosure
number. Enclosure 1 is always at the bottom of the chain.
•
FCSA population in an IOAM enclosure is from slot 1 to slot 5.
•
G4SA population in an IOAM enclosure is from slot 5 to slot 1.
•
In systems with two or more cabinets, primary and mirror disk drive enclosures
reside in separate cabinets to prevent application or system outage if a power
outage affects one cabinet.