HP-UX vPars and Integrity VM V6.3 Administrator Guide

5.4 Handling faulty CPU
On VSP with HP System Fault Management (HP SFM) software installed, if a faulty CPU is
encountered, a CPU deletion request is raised on the host kernel.
If the CPU identified for deletion happens to be a non-Monarch CPU of the running vPar, then it
can be dynamically deleted from the vPar. If the CPU is the Monarch CPU of the vPar, then the
CPU cannot be deleted.
Deleting a CPU on the VSP does not impact the running VM guests, as the entitlements are adjusted
dynamically by the HPVM scheduler with the other remaining physical CPUs that are present in
the vPar and Integrity VM guest pool.
5.5 Configuring memory for VM guests
5.5.1 Memory virtualization
When a VM guest is started, the memory from the vPars and Integrity VM pool is allocated and
presented to the guest as if it were private, physical memory. Each VM guest is provided with a
virtualized physical address space called guest-physical memory. The guest operating system
manages this guest-physical memory in exactly the same way the operating system manages
physical memory on an HP Integrity system. The VMM manages the mapping of guest-physical
memory to real-physical memory on the VSP. Any interaction of the guest operating system with
its memory management entities such as page tables and translation look-aside buffers are
intercepted by the VMM, controlling access to physical memory management structures. Maximum
memory supported for a VM guest is 256 GB.
5.5.2 Overhead memory for VM guests
Each VM guest has a memory overhead depending on its size. A rough estimation of the individual
guest memory overhead can be done using the following formula:
Guest memory overhead = cpu_count * guest_mem * 0.4% + 64M
where,
guest_mem is the VM guest memory size (in MB).
cpu_count is the number of vCPUs for VM.
For example,
For a VM with 4 vCPUs and 16GB memory, the overhead is 320MB,
For the same 16GB VM with 1 vCPU, it is ~128M.
When you create a 16GB 4vCPU VM, additional 320MB is used up by the VM. This memory is
taken from the vPar and Integrity VM guest pool. Note that there might be some amount of memory
taken up from the VSP memory when a guest is started. However, that is in most cases negligible
compared to the vPar and Integrity VM guest overhead memory taken up from the vPar and Integrity
VM guest pool.
The hpvmstatus –s command output displays additional information taking into account the
required guest memory overhead.
5.5.3 Dynamic memory
Dynamic memory is an optional feature of Integrity VM that allows you to change the amount of
physical memory in use by a VM without rebooting the VM.
When dynamic memory is enabled for an Integrity VM, it starts up with a range for memory size;
the range specifies a potential maximum and absolute minimum value. At any given time, based
on actual system usage, the amount of memory in use by the guest will be within this range.
Ensure to note the following:
58 CPU and Memory