System Sizing Guidelines for Integrity Virtual Machines Deployment -- Hardware Consolidation with Integrity Virtual Machines

14
Identifying Memory Available for Use by Virtual Machines
An additional 8.3% of memory is required by Integrity VM for memory to be used by a VM.
Therefore, if you define a VM to have 10 GB of memory, then Integrity VM requires 10.83 GB of
memory to instantiate that VM. Similarly, a VM defined with 4GB of memory requires
approximately 4.33 GB of memory to instantiate it. Note that these two VMs cannot be
instantiated concurrently on the physical server configuration described in the previous example
because the total required memory by the VMs is 15.16 GB of memory, but only 12.94 GB is
available.
You may calculate the amount of memory to be used in configuring VMs by dividing the total
memory available (after the VM Host requirements) by 1.083.
For the VM Host with 16GB in our previous example, the effective amount of memory available to
VM configurations is:
13.44 GB / 1.083  12.4 GB
As a result, we may configure two virtual machines with 5GB of memory each on this system (and
one of them may actually have 7.4 GB of memory).
When configuring virtual machines to use dynamic memory allocation or Integrity VM‟s Automatic
Memory Reallocation (AMR), the amount of memory defined for a VM may be more than the
amount summarized here. Consult the Integrity VM product documentation for more details.
Identifying the Capacity Requirements for a New VM Host
The previous section is based on the assumption that an existing server is to be used as a VM Host.
When consolidating multiple physical systems onto virtual machines – each with its own individual
capacity needs – one may need to size a new server. This section addresses the scenario in which
a new Integrity server will host a set of virtual machines.
Consider the deployment of several VMs on a single physical server. Suppose the total aggregate
VM mass storage (disk) capacity requirement is 550 GB and VM memory total is 28 GB.
Computing the Memory Capacity for the VM Deployment
Let us consider memory requirements first. Using the relations outlined above, sufficient physical
memory relates to the aggregate VM memory size as follows:
Physical memory ≥ 1.18 × (aggregate VM memory size) + 1.3 GB
For our example, this is:
Physical memory ≥ 1.18 × (28 GB) + 1.3 GB ≈ 34.34 GB
Note that memory requirements of I/O ports are not included in these inequalities and any such
requirements will increase the physical memory requirement.