Planning Virtual Machine Memory

Allocate memory to assign physical memory to a virtual machine (VM) on your ztC Edge system.

When allocating memory to a VM, consider the following information and restrictions:

• The total memory you can allocate to the VMs is equal to the total amount of memory available on the ztC Edge system (see System Requirements Overview) minus the memory allocated to the ztC Edge system software. For example, if the total amount of memory is 32 GB, and 2 GB is allocated to the system software, there are 30 GB of memory available to the VMs.
• For systems configured with two nodes, you can provision a single VM with memory up to the total amount of memory available to the VMs. Each VM consumes its requested amount of memory plus an additional 20% memory for overhead.
• The minimum memory allocation is 256 MB, but 64-bit operating systems require 600 MB or more. Be sure to verify the memory requirements for your guest operating systems.
• The System page of the ztC Edge Console (see the System Page) indicates the total amount of memory, the memory allocated to the ztC Edge system software, the memory consumed by running VMs, and the amount of free memory. Use this page to verify your memory allocations.
• The Stratus Redundant Linux software does not allow over-provisioning of memory for running VMs; it prevents you from starting VMs that would exceed the total physical memory of the physical machines. You may safely allow over-provisioning of memory to occur only if one or more of the VMs is stopped while the other is running, for example, during VM upgrades or VM point-in-time backup or recovery.
• If necessary, you can manually redistribute memory by shutting down or reconfiguring one or more under-utilized VMs and then reassigning the available resources to a more heavily-utilized VM.