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
Resource	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

Oversubscription Type	Description
Disc	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.
CPU	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)
Memory	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.

Oversubscription Type

Description

Disc

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.

CPU

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)

Memory

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.