HP-UX Virtual Partitions Administrator's Guide (includes A.03.05 and A.04.05)

Granularity Issues (Integrity and PA-RISC)
CAUTION: (vparcreate only) When you specify the granularity value for only one type of
memory (ILM or CLM), the granularity value for the other type of memory is set using the default
granularity value. For example, if you specify only -g ILM:256, the -g CLM:128 is implied
where 128 is the vPars default granularity value.
If your system (or nPartition) contains a large amount of memory (32 GB or more), you should set the
granularity value to the largest amount possible to reduce the total boot time (relative to boot time in
nPars/standalone) caused by the initial hardware scanning of memory. For CLM on PA-RISC platforms
and for both ILM and CLM on Integrity platforms, you should choose the largest possible granularity
value.
However, you should be careful when using the granularity option; using the option incorrectly
can cause all the virtual partitions to not be bootable.
Further, granularity in the vPars database can only be specified during the creation of the vPars
database. This means the first vparcreate command performed to create the database can be
used to specify the granularity, but it cannot be changed after that. It cannot be changed by
subsequent vparcreate commands nor any other commands; any change in values requires
the entire vPars database to be re-created. Therefore, read this section thoroughly.
For details on granularity values and granularity limitations, see the vparresources(5) manpage.
The granularity section of this manpage is provided below since there are critical notes in the
manpage of which you should know when planning a granularity value. These include:
• The minimum value for granularity of both ILM and CLM is 64 MB.
• The chosen granularity value(s) must be an integral power of 2 (in other words, 2^X).
• (Integrity only) There is a limit on the number of CLM granules per cell and total ILM
granules you can set. Use the vparenv command to see the maximum possible granules
for ILM and CLM for your specific system. For example:
# vparenv
vparenv: The next boot mode setting is "vPars".
vparenv: The ILM granule size setting is 128.
vparenv: The CLM granule size setting is 128.
vparenv: Note: Any changes in the above settings will become effective
only after the next system reboot.
vparenv: Note: The maximum possible CLM granules per cell is 64.
vparenv: Note: The maximum possible ILM granules for this system is 1024.
If either of these values are exceeded when you set your granularity values, the Monitor
will not boot any virtual partitions. You must rebuild your vPars database such that the
number of granules related to both ILM and CLM do not exceed the numbers in your
vparenv output.
• (PA-RISC only) Excluding the first granule, a portion of which is used by the Monitor, there
must be at least one entire granule that exists below the 2 GB limit for each virtual partition.
These granules below the 2 GB limit are used by kernel of each virtual partition.
• Especially for nPartitions or systems containing 32 GB or more of total memory, you should
set the granule to the highest possible granule size to reduce the time in scanning the memory
during the initial hardware boot.
• (Integrity only) In order for the virtual partitions in an active database to be able to boot,
the granularity values in the vPars database must match those written in the system firmware.
Granularity described in vparresources(5)
For reference, below is the granularity section of the manpage vparresources(5):
Granularity Issues (Integrity and PA-RISC) 219