One of the great benefits of the public cloud is that you can size your virtual machines and resize them as your business needs and as workload loads change. We can design the virtual network environment on which the VM will reside, and also plan for high availability.
Choosing the Right VM Size and Storage Option
While dealing with virtual machines and infrastructure as a service, also called IaaS in Microsoft Azure public cloud, we are talking about compute power.
To understand the Azure Compute Unit or ACU. Think about that you’re never going to see inside of an Azure data center, so you can’t see the physical blade servers that make up the server racks that are inside those data centers. You don’t know what the make and model of the specific hardware, so Microsoft has developed a standardization for compute power called the ACU. So 100 ACU is equivalent to a small, or standard A1 size virtual machine. Then as you look at the VM size lists in the Azure documentation, you can look at it as a factor of that 100 baseline.
There are a number of different virtual machine families, and they are optimized in terms of how they balance virtual processors and RAM and storage. Each family is going to have one or more sizes. These are denoted by integers and version numbers.
If we need to shift virtual machines that currently reside on-prem, we know how much virtual CPU, RAM, network bandwidth, and storage speed performance metrics we allocated to them on-prem. So we have to choose an appropriate size in Azure that will provide at least the same level of performance. Raise in the compute factors, will increase the per minute runtime charges as well, so one doesn’t want to overpay, but also doesn’t want to underpay.
Below provides you the breakdown in terms of a balance between CPU to memory and what kind of environments that virtual machine family and those sizes are intended for.
One great thing about the public cloud is that if you make the wrong choice and realize that VM size is too large or too small, all you need to do is to resize and reboot the virtual machine.
