# How to: Calculate DRaaS Hardware Plan Requirements

## Veeam Disaster Recovery as a Service (DRaaS) Failover Plans are designed to failover a virtual environment to the Probax Cloud using matching resource allocations.

### Resource calculation formulas

For optimal experience, Probax advises using the following calculations for each Hardware Plan requirement:

#### CPU

The CPU required is based on each virtual machine CPU allocation, and isn't dependent on the total host resources. Due to this, the recommended calculation is:

CPU Required = Total VM Cores x Base Clock Speed

Hypothetical example

A client is operating from a single host running Windows Server with a Intel® Xeon® Processor E3-1245 CPU (3.3 GHz). The hypervisor is operating 8 VMs, with 2 cores allocated to each VM.

CPU Required = 8 x 2 x 3.3 = 52.8 GHz

#### RAM

The RAM required is based on the total RAM consumed by each virtual machine.

RAM Required = Total Sum of Allocated RAM

Hypothetical example

A client is operating from a single host running Windows Server with 32 GB of RAM. The hypervisor is operating 8 VMs, with 26 GB RAM allocated across all VMs.

RAM Required = 26 GB

#### Number of Public IPs

The number of Public IPs required is dependent on how many public facing virtual machines are in the client environment, or how many virtual machines require an external IP for direct RDP access. The same public IP can be mapped to multiple virtual machines on multiple separate ports.

Hypothetical example #1

A client has 8 virtual machines, 3 of which are websites accessed via the world wide web and each site requires a separate public IP. To access these websites, three public IPs are required.

Hypothetical example #2

A client has 8 virtual machines, 5 of which need RDP access, but it is OK if they use non-standard RDP ports, so ports 3001 to 3305 can be used. Only one public IP is required.

#### Number of Networks

The number of networks required is dependent on how many networks exist on the client site that are being replicated to Probax.

Hypothetical example

A client has 10.0.1.0/24 and 10.0.0.0/24 allocated to their virtual machines will require two networks on the hardware plan.