HP-UX Virtual Partitions Administrator Guide (includes A.05.08) (5900-1312, March 2011)

B Problem with Adding Unbound CPUs to a Virtual Partition
(A.03.xx)
Unbound CPUs allow you to easily adjust processing power between virtual partitions. But a corner
case can occur where you will not be able to add specific unbound CPU(s) without rebooting the
target partition. This appendix discusses when this situation can occur and how to work around
it.
Symptoms
When attempting to add an unbound CPU, you may see the following error message:
One or more unbound CPUs were not available when virtual partition <partition_name> was
booted. You must shutdown the partition to add them.
This means that the unbound CPU cannot be dynamically added to the virtual partition.
Cause
When a virtual partition boots, the HP-UX kernel creates a table of the existing unbound CPUs
available at the time the virtual partition is booted. If there is not an existing entry in the table for
a specific CPU, that CPU cannot be added to the partition.
Example
To simplify the example, this appendix uses a generic eight-way (8-CPU) server whose CPUs are
at the hypothetical hardware paths of x01, x02, x03, x04, x05, x06, x07, and x08.
Create the Virtual Partitions
Suppose we create three partitions using the following commands.
# vparcreate -p vpar1 -a cpu::2 -a cpu:::2
# vparcreate -p vpar2 -a cpu::2 -a cpu:::2
# vparcreate -p vpar3 -a cpu::1
And suppose that the vPars Monitor chooses the following hardware paths for the bound CPUs:
vpar3vpar2vpar1Virtual Partition
x05x03
x04
x01
x02
Paths of Bound CPU(s)
This configuration leaves the following three CPUs as unbound CPUs:
x06, x07, x08Paths of Unbound CPUs
Boot the Virtual Partitions
When we boot the partitions, they will boot with the following bound CPUs; their respective kernels
will have the following unbound CPU entries.
Note that the entries for the unbound CPUs are only entries for unbound CPUs that can potentially
be added to the partition. At this point, we have not assigned any unbound CPUs to any of the
partitions:
vpar3vpar2vpar1Virtual Partition
x05x03
x04
x01
x02
Paths of Bound CPU(s)
Symptoms 283