Square Peg in a Round Hole

Are Windows workloads suitable for AWS?

With so much buzz about moving workloads to the public cloud, to save money and improve scalability I think we have forgotten something. The public cloud is not the same thing as a private cloud.

I recently attended AWS training, Architecting for high availability and the instructor said something that I had to think about. He said that hosts will fail and bring down your instances, as a matter of fact. And that we should be architecting to allow for this type of outage.
I’ve been working with VMware for so long that I don’t need to architect my instances or VMs for Host failure. With HA turned on I can be fairly certain that if a Host does fail, the VMs will power up on another host and service will resume. And VMware vSphere is a mature product that Hosts only fail when there is a hardware problem.

So this raises the question, as an example, can I move my Windows File Servers to AWS with confidence? What happens when a Host fails, my file server instance goes down and I have to restore from S3? Sure I could add redundancy at the application level, using Microsoft clustering but that is just adding complexity and cost.

There are some cases that Windows workloads can fit AWS, for example an RDS or a Citrix Farm, as there is some application layer redundancy.
I guess there are solutions to replace file servers, but in the rush to save money and move workloads to the public cloud we are just lifting and shifting. This isn’t taking advantage of the public clouds capabilities and is possibly costing us more for an inferior product.
Public cloud makes sense for applications written for the public cloud. Applications architected with the “Everything fails all the time” mentality. But is it a better solution for our existing Windows workloads?

Maybe we should delineate the two by just maintaining the old and nurturing the new.

Pricing comparisons in the cloud

A comparision of public cloud pricing

There are many things to consider when thinking of moving workloads to the cloud. There is a common misconception that cloud is cheaper than whatever you are doing right now. There is a chance that it isn’t cheaper but there are other benefits to factor in to the price. However price is still a factor which is why I conducted my own cloud comparison.

It is nearly impossible to compare apples with apples when it comes to comparing virtual machine resources between different clouds. But I’ve tried to simplify the comparison by choosing a standard sized VM which would be suitable for a mid-sized Windows Server.

The comparisons are based on an unmanaged VM with 4vCPU, 8GB of Memory, 100GB System Partition, 1TB data partition and a basic backup.

When viewing these comparisons please be aware that not everything is equal. There are slight discrepancies between:

  • The Number of CPUs allocated
  • The speed of the CPUs allocated
  • The amount of memory allocated
  • The type of storage allocated
  • The contention ratio of CPU and Memory