Introduction to the HP Virtual Server Environment

Chapter 4: HP Partitioning Solutions
This chapter discusses the partitioning solutions available for HP Integrity servers, with a particular
emphasis on how each of these solutions can be made dynamic.
nPartitions
HP nPartitions are implemented in hardware on HP cell-based servers. Each nPartition consists of one
or more cells, each with a physical group of processors, memory, and I/O cards. This is
implemented via a state-of-the-art chipset that allows any combination of cells to be electrically
isolated from cells in other partitions. Figure 2 shows how the cells are connected to crossbars
(labeled “xbars”) on the backplane of a Superdome server using the sx2000 chipset. Note that all
the connections between the cells and the crossbars are triple redundant for high availability. Each of
the links can also be programmatically configured to drop electrical signals if the source and
destination cells are not in the same partition.
HP nPartitions can flex dynamically in 2 ways:
1) Using Dynamic nPartitions. This allows you to add or remove a cell board (and its associated CPU
and memory, and any attached I/O) to or from an nPartition without shutdown or reboot.
2) Using iCAP (described in the next chapter). This feature allows the number of active CPUs in each
partition to be dynamically adjusted while the partitions remain running.
Figure 2. Connectivity among cells and crossbars (sx2000 chipset)
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