HP-UX Virtual Partitions Administrator Guide (includes A.05.07) (5900-1229, September 2010)

Memory: Specifying Address Range
Within the already allocated memory sizes, you can specify the memory address ranges using
the mem:::base:range syntax. However, this is not recommended unless you are familiar with
using memory addresses. For PA-RISC systems, you should also be familiar with the requirement
that all HP-UX kernels fit within 2 GB of memory, as described in “2 GB Restriction (PA-RISC
only)” (page 225).
For usage information, see the vparmodify(1M) manpage. You should select your base:range
after consulting vparstatus -A to determine which ranges are available.
CAUTION: Normally, ranges are granule-aligned (in other words, the starting address and the
ending address of the range is a multiple of a granule). However, due to memory fragmentation,
some of the ranges may not be granule-aligned. It is not recommended to assign such nongranule-
aligned ranges as user-specified ranges (mem:::base:range). Further, future vPars releases may
not support specifying ranges that are not aligned to a granule and may return an error when
such ranges are assigned to a virtual partition.
NOTE:
• Specifying an address range does not increase the amount of memory assigned to the
partition. Rather, it only specifies addresses to use for the already allocated memory sizes.
Therefore, all specified ranges cannot exceed the total allocated memory for the virtual
partition. In other words, the sum of the ILM- or CLM-specified ranges cannot exceed the
total amount of ILM or CLM memory reserved for the virtual partition.
• (vPars A.04.xx) Address ranges are unique within a given virtual partition. Therefore,
specifying base:range (and not a cell_ID) is sufficient for using an address range within
CLM. You can use vparstatus -A to list the available ranges and whether the ranges are
a part of ILM or CLM. Further, if the range is within CLM, vparstatus -Aalso lists to
which cell the range belongs.
2 GB Restriction (PA-RISC only)
When ranges are specified for the entire memory owned by a partition, you should ensure that
at least one of the ranges is below 2 GB and is large enough to accommodate the kernel for that
partition. However, other partitions also require memory below 2 GB for their kernels. Hence,
you also should ensure that the specified range below 2 GB is not so large such as to preclude
memory below 2 GB for the other partitions.
In general terms, the sum of the size of the kernels must be < 2 GB. To calculate the kernel sizes,
see “Calculating the Size of Kernels in Memory (PA-RISC only)” (page 317).
CAUTION: Not allowing enough memory for the other partitions will cause the other partitions
to not boot. You can boot the partition by freeing up enough memory for the partition to boot,
such as by shutting down an active partition.
If no memory ranges are below 2 GBs for a given partition, the partition will not boot.
If you use the defaults of the dynamic tunables, you will not run into the 2 GB limit. However,
if you have adjusted the dynamic tunables, it is possible to run beyond the 2 GB boundary. For
more information on adjusting the kernel size with dynamic tunables, see the white paper
Dynamically Tunable Kernel Parameters at http://docs.hp.com.
Memory: Specifying Address Range 225