HP RX8620-32 - Manual (Page 15)

15
Cell hot-plug
The HP Integrity rx7620-16 and rx8620-32 Servers support cell hot-plug. Coupled with the servers’
partitioning capability
1 , cell hot-plug allows for the servicing of cell boards within a single partition
while the other partition continues normal operation. Any number of configuration changes can be
made to the partition being serviced, including replacing the complete cell board, adding or deleting
CPUs and memory, or even increasing or decreasing the number of cells in that partition. (Cell hot-
plug is supported only in systems with two or more partitions.)
Crossbar backplane
The next basic building block of the Integrity rx8620-32 Server is the crossbar backplane. The
crossbar backplane contains two crossbar chips that provide a non-blocking connection between four
cells and their associated memory and I/O. (The Integrity rx7620-16 Server does not have a crossbar
backplane, so communication between its cells is over a direct-connect bus.)
Crossbar chips
The crossbar ASIC is yet another part of the HP sx1000 Chipset. The Integrity rx8620-32 Server
crossbar consists of two chips. Each chip implements a high-performance 8-port non-blocking crossbar
and the 500 MHz crossbar link protocol. Together, the two crossbar chips provide 16 high-
performance ports for cell-to-cell communication, with 8 GB/s of bandwidth available for each cell.
All ports are functionally and electrically identical. Some of the features of the crossbar chip that
contribute to performance include the following:
• Support for scaling up to a 128-way coherent shared memory system
• 250 MHz speed of operation
• 500 MT/s (mega transfers/second) link speed
• Support for two interleaved channels on link protocol
• Support for double-length data packets for Intel Itanium Processor Family mode
• Performance counters to enable software tuning
The crossbar mesh implements a global point-to-point packet filtering network. This mesh features an
extremely high level of integrity, with each crossbar port operating independently. The crossbar mesh
has dedicated paths for data and control. Each port can be reset, assigned, or reconfigured fully
independent of other ports. The crossbar mesh of the HP Integrity rx8620-32 Server is an excellent
foundation for resource isolation.
1 The Integrity rx8620-32 server can be configured as a single large SMP server or hardware-partitioned into up to four smaller logical servers.
See “nPartitions” for more details about partitioning.