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

Modular System Hardware
HP Integrity NonStop NS-Series Planning Guide—529567-004
2-11
Logical Synchronization Unit (LSU)
Front Panel Indicator LEDs:
Logical Synchronization Unit (LSU)
The LSU is the heart of both the high-availability duplex processor complex and the
fault-tolerant triplex processor complex. In the current Integrity NonStop NS-series
systems, each LSU is associated with only one logical processor.
The LSU is the ServerNet fabrics gateway for the duplex or triplex processor
complexes. It ensures that I/O from logical processors is valid before allowing it into the
ServerNet fabric. The LSU module compares I/O streams between the output of each
CPU slice to ensure validity of the data. No data leaves the confines of a single slice
without being compared to and validated with the data from the other slice (duplex
processor) or the other two slices (triplex processor).
The LSU enclosure, which is 4U high and weighs 95 pounds (43 kilograms) when fully
populated, has these physical attributes:
•
Rack mountable
•
Redundant AC power feeds
•
Front to rear cooling
•
Connections for three processor slices
•
Connections for two ServerNet fabrics
•
Cable management and connectivity on the rear of the cabinet
Logically the LSU:
•
Implements a fault domain that affects only a single logical processor
•
Has environmental sense and control (ESC) aspects managed by the logical
processor
•
Supports single-point system power-on
The LSU module consists of two types of FRUs:
•
LSU logic board (accessible from the front of the LSU enclosure)
•
LSU optics adapters (accessible from the rear of the LSU enclosure)
•
AC power assembly (accessible from the rear of the LSU enclosure)
LED
Indicator State Meaning
Power Flashing green Power is on; slice is available for normal operation.
Flashing yellow Slice is in power mode.
Off Power is off.
Fault Steady amber Hardware or software fault exists.
Off Slice is available for normal operation.
Locator Flashing blue System locator is activated.