NonStop NS-Series Planning Guide (H06.05+)

Integrity NonStop NS16000 System Description
HP Integrity NonStop NS-Series Planning Guide—529567-008
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Failure Recovery for Triplex Processor
Failure Recovery for Triplex Processor
In triplex processors, each LSU has inputs from the three processor elements within a
logical processor. As with the duplex processor, the LSU keeps the three PEs in loose
lockstep. The LSU also checks the outputs from the three PEs. If outputs from one of
the PEs is not the same as the other two, the errant result is ignored, and the result
from the other two PEs is sent to the ServerNet fabrics. Reintegration works the same
as in the duplex processor. The number of PEs in a reintegration depends on the
conditions of the failure and the configuration of the hardware.
The failure of a NonStop Blade Element in a triplex processor reduces processor
operation to duplex. When the failing unit is replaced, the reintegration function
restores the system to triplex operation. If failure of an LSU takes down its associated
logical processor, the operating system activates the backup processes in other logical
processors. The system runs user applications as if no failure occurred.
As with a duplex processor, the errant processor is reset, and then it is synchronized
with the running processors. If the failure rate exceeds a predetermined threshold
value within a period of time, the failing processor is reset and held for repair action.
ServerNet Fabric I/O
This subsection provides information about the ServerNet network in an Integrity
NonStop NS-series system and covers these topics:
For further information on the ServerNet network, protocols, IP addresses, and naming
conventions, see the Introduction to Networking for Integrity NonStop NS-Series
Servers.
Overview
ServerNet 3 routers are used within the Integrity NonStop NS16000 systems as
building blocks for the ServerNet fabric, which employ fiber-optic links exclusively and
is a collection of connected routers and links that form a flexible internal or external
network. This high-speed network within an Integrity NonStop NS16000 system
connects NonStop Blade Complexes to the ServerNet adapters and system I/O such
as disks and Ethernet LANs by way of the switch boards in the p-switches and IOAM
enclosures. ServerNet connections can also exist to NonStop S-series I/O enclosures.
Topic Page
Overview
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Simplified ServerNet System Diagram 4-10
P-Switch ServerNet Pathways 4-11
IOAM Enclosure ServerNet Pathways 4-12
Example System ServerNet Pathways 4-13