NonStop NS1000 Planning Guide (H06.08+)

For more information, see “Fibre Channel Disk Module” (page 62).
Factory-Default Locations for Disk Volumes
This illustration shows where the factory-default locations for the primary and mirror system
disk volumes reside in separate Fibre Channel disk modules:
Fibre Channel port location and cable connections vary depending on the various controller and
Fibre Channel disk module combinations.
Configurations for Fibre Channel Devices
Each VIO enclosure in an Integrity NonStop NS1000 system contains four Fibre Channel ports
that support up to 16 Fibre Channel disk modules (FCDMs) in a daisy-chained configuration,
with identification of the FCDMs depending on the ServerNet connection to the Fibre Channel
ports on the VIO enclosure.
Configuration Restrictions for Fibre Channel Devices
These configuration restrictions apply and are invoked by Subsystem Control Facility (SCF):
• Primary and mirror disk drives in FCDMs cannot connect to the same Fibre Channel loop.
Loss of the Fibre Channel loop makes both the primary volume and the mirrored volume
inaccessible. This configuration inhibits fault tolerance.
• Disk drives in different FCDMs within 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 Fibre Channel ports in the same VIO enclosure. Loss of one Fibre Channel
port can make multiple disk drives inaccessible on a single Fibre Channel communications
path. This configuration is allowed, 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 Fibre Channel ports in the same VIO enclosure. Loss of one Fibre
Channel port can make multiple disk drives inaccessible on a single Fibre Channel
communications path. This configuration is allowed, but only if you override an SCF warning
message.
84 System Configuration Guidelines