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Partitioning

A hardware partition corresponds roughly to a single, standalone system. The HP 9000 rp8420 Server
can be subdivided into four partitions, each containing one or more cells that communicate coherently
over a high bandwidth, low latency crossbar fabric. Cells are grouped into physical structures called
cabinets or nodes. Special programmable hardware in the cells defines the boundaries of a partition in
such a way that the isolation is enforced from the actions of other partitions. Each partition runs its own
independent instance of the operating system. Applications cannot span partitions since each partition
runs its own instance of the OS, essentially functioning as a stand-alone server. However, different
partitions may be executing the same or different revisions of an operating system.

Each partition has its own independent processor modules, memory and I/O resources consisting of the
resources of the cells that make up the partition. Resources may be removed from one partition and
added to another without having to physically manipulate the hardware just by using commands that are
part of the System Management interface. With a future release of HP-UX, using the related capabilities
of dynamic reconfiguration (e.g. on-line addition, on-line removal), new resources may be added to a
partition and failed modules may be removed and replaced while the partition continues in operation.
Partitioning the resources of the complex in this way makes it easy to run multiple applications on the
same physical system; you can allocate physical resources and tune the operating system running on
each partition depending on the needs of the application (or the most important application) you intend
to run on it. Alternatively, you can configure the HP 9000 rp8420 Server as a single partition, allowing
all the resources to be focused on a single set of tasks, for example a large online transaction-processing
application.

You can increase or reduce the processing power of a partition by adding or deleting cells (with the
current HP-UX release, you must shut down the operating system running on the affected partition(s)
before moving cells, and before configuration changes will take effect). Though HP-UX 11i does include
commands for some configuration tasks, HP recommends you use the Partition Manager (parmgr) to
configure partitions.

The current release of HP 9000 rp8420 Server/HP-UX 11i supports hardware partitioning. Hardware
based partition configuration changes may require a reboot of the partition depending upon the
configuration change. The reboot of the partition only affects the partition that is being reconfigured. The
other partition defined in the chassis is not affected and will continue to execute without interruption. In a
future HP-UX release, dynamic hard partitions will be supported. Dynamic partitions imply that partition
configuration changes do not require a reboot of the partition.

The HP 9000 rp8420 Server can be divided into four independent hardware partitions when configured
with the rp84xx/rx86xx Server Expansion Unit. In a partitioned configuration, I/O bay resources such as
I/O slots, core I/O, disk and removable media bays, are always dedicated to the corresponding cell
board slot. In other words, I/O bay 0 resources are always configured to the cell board in Cell slot 0.
Therefore, in a partitioned system, the amount of resources within a partition is always proportional to
the number of cells within that partition. There is no flexibility to otherwise divide these components. For
example, in a system configured with two cells in separate nPars, it is not possible to include twelve I/O
slots in partition 0 and four I/O slots in partition 1. Please refer to the "HP Server Expansion Unit" section
in this guide or more specific details.

The table below summarizes the resource availability based on hardware partitions.

Number of Hard

Number of Hard
Partitions

Partitions

Minimum # of Cells

Available I/O slots (min)

Available I/O slots (min) Core I/O (required)

Core I/O (required)

Available Disk/Media

Available Disk/Media
Bays (min)

Bays (min)

1 Partition