Technical data

Introduction to nPartitions
nPartition Requirements and Recommendations
HP System Partitions Guide: Administration for nPartitions—rp7410
EMSP—[e-mail]
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•Youshould assign multiple core-capable cells to each nPartition.
This allows the partition to boot at least to the BCH interface if a core
cell fails to boot.
(Disregard this recommendation if you are configuring multiple
partitions in an HP rp8400 server or HP rp7410 server, each of which
has a maximum of two core cells.)
• The memory configuration of all cells in a partition should be
identical to achieve best performance.
Each of a partition’s cells should have:
— the same number of DIMMs
— the same capacity (size) and the same locations (population) of
DIMMs
This avoids cell interconnect (crossbar) “hot spots” by distributing
memory evenly across all of the nPartition’s cells.
• The memory configuration of each cell should include a multiple of
two memory ranks per cell.
Each memory rank is 4 DIMMs. If possible, install memory in sets of
8 DIMMs: 8 DIMMs or 16 DIMMs on HP rp8400 and HP Superdome
cells. On HP Superdome cells, you also can install 24 DIMMs or
32 DIMMs per cell.
This provides a performance improvement by doubling the cell’s
memory bandwidth, as compared to having one memory rank
installed.
This also can provide an availability improvement, in that if one
memory rank fails the cell still has at least one functional rank of
memory.
(At this time memory rank 0 must be functional for a cell to boot.)
• Each nPartition should have PRI (primary), HAA (high-availability
alternate), and ALT (alternate) boot paths defined and configured,
and their path flags appropriately configured for your purposes.
The PRI and HAA paths should be configured to reference disks that
are connected to different cells, if possible, with HAA being a mirror
of the root volume and PRI being the root volume. ALT should refer to
a recovery or install device.
HP Restricted / DRAFT
DRAFT NOV 2001