HP Integrity Virtual Machines Installation, Configuration, and Administration

# hpvmmgmt -V -l ram
[Dynamic Memory Information]
=======================================
Type : driver
Current memory : 2103 MB
Target memory : 2103 MB
Comfortable minimum : 2423 MB
Minimum memory : 1222 MB
Maximum memory : 6144 MB
Boot memory : 6135 MB
Free memory : 124 MB
Available memory : 286 MB
Memory pressure : 12
Memory chunksize : 65536 KB
Driver Mode(s): STARTED ENABLED GUESTCTL
To modify the guest memory to 4 GB, enter the following command:
# hpvmmgmt -x ram_target=4096M
Attempting to increase memory from 2103 MB to 4096 MB.
Successfully began to change ram_target to 4096 MB.
9.6.3 Troubleshooting Dynamic Memory Problems
This section describes how to solve problems in the use of dynamic memory.
9.6.3.1 Dynamic Memory Restrictions
Use of dynamic memory is subject to the following restrictions:
• The size of a virtual machine cannot be increased above its original boot size (as specified
with the -r option).
• If the virtual machine memory has become fragmented , attempting to reduce the size of
the virtual machine may not succeed or may take a very long time. If you cannot reduce the
size of the virtual machine to the desired size, abort the operation by setting a new target
size.
• Increasing the size of a virtual machine requires free memory on the VM Host. If the VM
Host memory is insufficient, the operation may take a very long time to complete and may
fail.
• If the values of ram_target and ram_dyn_target_start are not inside the values of
ram_dyn_min and ram_dyn_max, a warning is issued.
9.6.3.2 VM Host Performance Considerations
HP-UX supports “large pages”, a memory management feature used to improve performance.
Integrity VM takes advantage of this feature by ensuring that when a virtual machine starts, it
allocates the largest size pages that are available. Once these pages are allocated and locked down
they cannot change size. This keeps fragmentation of large pages to a minimum.
This feature limits the types of software you can run on a VM Host system. If the VM Host system
supports an additional workload beyond the virtual machines, the large pages tend to fragment
and performance of the newly-started virtual machine may degrade.
Dynamic memory increases the possibility for VM Host memory to become fragmented. The
current implementation of dynamic memory releases portions of the memory allocated to a
virtual machine. These operations must be performed in large contiguous chunks; otherwise,
the act of reducing the size of a virtual machine fragments the VM Host memory allocated to it.
This potential fragmentation is prevented by the software, which reduces a vitual machine's size
only in multiples of a minimum chunk size of 64 MB of physically contiguous memory. For more
information, see Section 9.6.3.4: “Specify Sufficient Guest Memory” (page 126).
9.6 Dynamic Memory 125