HP Integrity Virtual Machines 4.2: Installation, Configuration, and Administration
addition to the amount of memory you specify for the virtual machine, the VM Host requires a
certain amount of overhead for booting the guest operating system. The amount of memory
allocated to all the running guests cannot exceed the amount of physical memory minus the
amount used by the VM Host for its operating system and its administrative functions. For more
information about the memory requirements of the VM Host, see Section 2.1 (page 27).
Guest memory allocation can be viewed and allocated dynamically (that is, without stopping
the guest) by using dynamic memory parameters, as described in Section 9.7 (page 151).
3.2.6 Automatic Cell Balancing
When creating a guest, Integrity VM determines the best fitting locality domain for the new guest
when the VM Host is predominantly Cell Local Memory(CLM) or the guest has the
sched_preference flag set to cell with the hpvmmodify, hpvmcreate or hpvmclone
command. Integrity VM uses this setting as a guide for run-time scheduler planning as well as
guest boot time CPU and memory binding. The hpvmstatus -C command provides a list of
guests with their memory type.
If you do not use CLM at all, then all the guests use Interleaved Memory (ILM). If however, CLM
is set, every hpvmstart command checks whether Integrity VM chooses cell or interleaved
for this particular guest, and if cell is chosen, which cell it is. For example, you have an 8 GB VM
Host configured with 75 percent CLM and 25 percent ILM. With two cells, each contributes 3
GB to cell local and 1 GB to interleaved. On boot, the operating system takes 1GB of the interleaved
memory. If each guest takes 1 GB to start, the breakdown looks like this:
• guest 1: cell 0 (2 GB CLM left)
• guest 2: cell 1 (2 GB CLM left)
• guest 3: cell 0 (1 GB CLM left)
• guest 4: cell 1 (1 GB CLM left)
• guest 5: cell 0 (no CLM left)
• guest 6: cell 1 (no CLM left)
• guest 7: interleaved (no memory left at all)
The general trend is for CLM if any cell has at least as much free space as the available ILM.
3.2.7 Virtual Devices
Use the -a option to allocate virtual network switches and virtual storage devices to the virtual
machine. The VM Host presents devices to the virtual machine as “virtual devices.” Attached
I/O devices, such as tape, DVD burner, and autochanger, are not presented as virtual devices;
they are presented as direct I/O devices. You specify both the physical device to allocate to the
virtual machine and the virtual device name that the virtual machine will use to access the device.
The following sections provide brief instructions for creating virtual network devices and virtual
storage devices.
3.2.7.1 Creating Virtual Network Devices
The guest virtual network consists of:
• Virtual network interface cards (vNICs)
• Virtual switches (vswitches)
For virtual machines to communicate either with other virtual machines or outside the VM Host
system, each virtual machine's virtual network must be associated with a virtual switch (vswitch).
If you start a virtual machine without a vswitch, the virtual machine has no network
communication channel.
Each guest can have two different types of LAN network devices, VIO and AVIO. For VIO guest
networks, a vswitch functions just like a physical network interface card (pNIC), accepting
network traffic from one or more virtual machines and directing network traffic to all of its ports.
A vswitch without the backing of a host physical network card can be used by VIO guest devices
3.2 Specifying Virtual Machine Characteristics 47