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

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-specified ranges cannot exceed the total amount of ILM memory
reserved for the virtual partition.
2 GB Restriction
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 286).
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, go to the BSC website at
www.hp.com/go/hpux-networking-docs, click HP-UX 11i v3 Networking Software and see the
white paper Managing NFS and KRPC Kernel Configurations in HP-UX 11i v3.
Memory: Allocation Concepts and Notes
• The unit for the specified size of memory for the vPars commands is megabytes; parmodify
uses gigabytes.
• The default memory assigned to a virtual partition is 0 MB, so you need to specify enough
memory for your applications and the operating system. While there is no specific minimum
base memory requirement per vpar, the HPUX kernel does require a certain amount of base
memory to boot successfully. For this reason, we currently recommend that 1 GB of base
memory is assigned per vpar. The more base memory a virtual partition has, the better the
performance will be. This is especially true of applications that require large amounts of locked
memory. See the Installation and Update Guide for your OS and the nPartition Administrator’s
Guide for your server.
• Memory is allocated in multiples of 64 MB. Any specified size that is not a multiple of 64 MB
is rounded up to the nearest 64 MB boundary. For example, if you specify 1 MB, 64 MB will
be allocated.
Memory: Allocation Concepts and Notes 237