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

Example 2
If the total physical memory is 100 GB, then the granularity value should be 2 GB:
100 GB / 2 GB => 50 granules
Note that as seen in “Granularity Issues (Integrity and PA-RISC)” (page 213) and in the
vparresources(5) manpage, memory is allocated to a virtual partition as a multiple of the granularity
value. In this example, given a granularity value of 2 GB, this means that every virtual partition
will have at least 2 GB (1 multiple) allocated to it. Further, this means that any memory assigned
between the multiples will be rounded up to the next multiple. For example, if you attempt to assign
3 GB of memory to a virtual partition, this actual memory allocated will be rounded up to the next
granularity multiple, in this case, of 4 GB.
If having each virtual partition allocated with at least 2 GB of memory is not desired, then you
must chose a granularity value that is less than 2 GB, noting that this will cause the number of
granules to be higher than 50 and therefore increase boot time.
NOTE:
PA-RISC
Due to PA-RISC and Integrity architectural differences, the way memory is presented to HP-UX on
PA-RISC systems is different than on Integrity systems, so PA-RISC systems do not encounter this
slow boot issue.
Memory: Setting the Granularity Values (Integrity)
Syntax
The syntax for setting granularity unit size is:
-g ILM|CLM:unit[:y|n]
where:
-g is granularity
ILM|CLM specifies whether the unit size is applied to ILM or CLM
unit is the granularity unit size in MBs
This value must be an integral power of 2 (in other words, 2^X) and be greater than
or equal to 64.
y|n specifies whether the granularity unit size should be written to firmware. The default
is n.
(vparcreate only; Integrity only)
The default granularity is 128 MB for ILM and 128 MB for CLM.
Commands
There are two commands that can set the granularity values: vparenv and vparcreate. Both
are available at the HP-UX shell level and use the -goption:
1. vparenv -g ...
writes the granularity values to the firmware only. Note that vparenv is applicable only on
Integrity.
2. vparcreate -g ...
writes the granularity values to the vPars database and also can (using the update firmware
option [:y]) write these values to firmware.
216 CPU, Memory, and I/O Resources (A.04.xx)