Recommendations for VM Resource Allocation

The allocation of resources for the Vocera Platform (i.e., processor, memory, etc.) for optimal performance depends on factors such as the volume of inbound data, processing overhead of the data type, and the complexity of the solution implemented.

Resource Allocation for Small and Large Installations

It is not always practical to conduct a detailed analysis at the start of every project to determine the correct hardware selection. You can determine the virtual machine (VM) resource allocation requirements for your implementation using the information in the following tables.

Resource Small Installations Large Installations
With Voice With Voice and Integration With Voice and Integration
Concurrent users <450 <450 450-2000
Processor Type Intel Xeon CPU Intel Xeon CPU Intel Xeon CPU
Frequency 3.20GHz 3.20GHz 3.60GHz
Cores/Threads 4/4 4/8 8/8
Memory 8GBytes 8GBytes 20Gbytes
Hard Disk (raw size) 300GB 300GB 800GB


Oversubscription Type Description
  • No disk oversubscription is allowed on the host.
  • All virtual disks should use a “thick” provisioning method.
  • Only direct-attached storage is recommended.

Recommendation: If you are using NAS or SAN, the maximum disk latency should be in line with the best practices for a real-time Voice application. For more information, see VMware vSphere® 5.5 Documentation Center.

  • No CPU oversubscription is allowed on the host.
  • The amount of provisioned vCPU's should be one less than the amount of physical processor cores available in the hypervisor (ESXi host).
  • CPU affinity is not required or recommended.
  • Hyper-threading can be enabled but additional logical processors made available via the hyper-threading feature do not count toward the provisioning totals.
For example, when the host machine contains 2 quad-core processors with hyper-threading enabled:
  • Physical CPUs = 8
  • Logical processors = 16
  • Maximum vCPU’s allowed = 7 (8 – 1 available for hypervisor use)
  • No memory oversubscription is allowed on the host.
  • Provisioned memory of all virtual machines combined should equal 1GB less than the amount of memory installed in the hypervisor.

For example, when the host machine contains 24 GB of RAM, 24 – 1 = 23 GB of RAM is available for guest VMs memory allocation.