NonStop NS1000 Planning Guide (H06.08+)

In the event of a processor fault, the failed component within a blade element (fan or power
supply) or the entire blade element can be replaced while the system continues to run. A single
Integrity NonStop NS1000 system can have up to eight blade elements for a total of eight
processors. Processors communicate with each other and with the system I/O over dual ServerNet
fabrics.
In the term ServerNet fabric, the word fabric is significant because it contrasts with the concept
of a bus. A bus provides a single, fixed communications path between start and end points. A
fabric is a complex web of links between electronic routers that provide a large number of possible
paths from one point to another. Two ServerNet communications fabrics, the X and Y, provide
redundant, fault-tolerant communications pathways. If a hardware fault occurs on one of the
ServerNet fabrics, communication continues on the other with hardware fault recovery transparent
to all but the lowest level of the OS.
Input/output components tap into the ServerNet fabrics through Fibre Channel and Ethernet
ServerNet functionality in the VIO enclosures in the preceding diagram of the NS1000 system.
The Fibre Channel and Ethernet functionality in the VIO enclosures provides the system I/O to
Fibre Channel storage devices and Gigabit Ethernet communications networks.
Although the hardware architecture differs from one series of NonStop servers to another, the
Integrity NonStop NS1000 system can be networked with other NonStop systems using the same
message system and the same network software.
38 Integrity NonStop NS1000 System Description