NonStop NS16000 Series Planning Guide (H06.11+)

and disk drives always have a fixed logical location with standardized location IDs of
group-module-slot. Only the group number changes as determined by the enclosure position in the
ServerNet topology.
However, the Integrity NonStop NS16000 series systems have no fixed boundaries for the hardware
layout. Up to 60 FCSA (or 120 ServerNet addressable controllers) and 240 Fibre Channel disk
enclosures, with identification depending on the ServerNet connection of the IOAM and slot housing
in the FCSAs.
Configuration Restrictions for Fibre Channel Devices
To avoid creating configurations that are not fault-tolerant or do not promote high availability,
these restrictions apply and are invoked by Subsystem Control Facility (SCF):
• Primary and mirror disk drives 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 Fibre Channel disk modules 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. In a fully populated system, loss
of one FCSA can make up to 56 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 FCSAs in the same module of an IOAM enclosure. In a fully populated system,
loss of one FCSA can make up to 56 disk drives inaccessible on a single Fibre Channel
communications path. This configuration is allowed, but only if you override an SCF warning
message.
Configuration Recommendations for Fibre Channel Devices
These recommendations apply to FCSA and Fibre Channel disk module configurations:
• Primary Fibre Channel disk module connects to the FCSA F-SAC 1.
• Mirror Fibre Channel disk module connects to the FCSA F-SAC 2.
• FC-AL port A1 is the incoming port from an FCSA or from another Fibre Channel disk module.
• FC-AL port A2 is the outbound port to another Fibre Channel disk module.
• FC-AL port B2 is the incoming port from an FCSA or from a Fibre Channel disk module.
• FC-AL port B1 is the outbound port to another Fibre Channel disk module
• In a daisy-chain configuration, the ID expander harness determines the enclosure number.
Enclosure 1 is always at the bottom of the chain.
• FCSAs can be installed in slots 1 through 5 in an IOAM.
• G4SAs can be installed in slots 1 through 5 in an IOAM.
• In systems with two or more cabinets, primary and mirror Fibre Channel disk modules reside
in separate cabinets to prevent application or system outage if a power outage affects one
cabinet.
• With primary and mirror Fibre Channel disk modules in the same cabinet, the primary Fibre
Channel disk module resides in a lower U than the mirror Fibre Channel disk module.
• Fibre Channel disk drives are configured with dual paths.
• Where possible, FCSAs and Fibre Channel disk modules are configured with four FCSAs and
four Fibre Channel disk modules for maximum fault tolerance. If FCSAs are not in groups of
Fibre Channel Devices 95