Vapor Versus Vendor

I'm interested in cloud versus owned IT cost comparisons. Understanding how organizations break out costs and set up the comparisons is insightful to their views and thinking. Some comparisons don't include the multitude of overheads, for example, management, facilities, procurement, engineering, and taxes because these costs are hidden or difficult to estimate.

A friend sent me a pointer to the up.time blog post. The author is comparing his in-house test environment against running a similar test infrastructure on AWS. AWS is for commonly used for building test environments. The post does a good job of breaking out in-house costs and tracking AWS expenses. The author factors some overheads into the analysis. The result? AWS costs $491,253.01 per year ($40,937.75 per month) more than his in-house environment. Wow!

There must be some mistake. The author must have left out something.

I can argue some minor points. For example, an average month has 30.5 days instead of 31 days, trimming about $1,000.00 per month off the $64,951.20 in instance charges. Another could be that the overhead should include additional overheads mentioned above. These minor points may add up to $5,000.00 per month, a far cry from explaining the $40,937.75 per month delta.

Looking a bit deeper, there is a big cost difference between 150 Linux and 100 Windows instances. Breaking out a baseline of Linux costs (to cover AWS machine, power and other costs) versus the additional cost for Windows. The baseline price for 302 Linux small and large instances is $22,915.20 per month. The Windows premium is $0.025 per CPU hour and that works out to $2,827.00 per month for 152 Windows instances. The cost for Windows and SQL Server running on 152 instances is $42,036 per month. Hence, the SQL Server premium is approximately $39,171.60 per month. The author pays $4,166.00 per month for his in-house database licenses. The premium paid for SQL Server on AWS is approximately $35,005.06 per month.

Most of the $40,937.75 per month cost disadvantage for the cloud can be explained by the AWS pricing for Microsoft Windows at $2,827.00 per month and SQL Server at $35,005.06 per moth. If the author would allow me, I could haggle the overheads and other minor issues to close the remainder of the gap. But, that's not the real issue here.

The pricing for Windows and SQL Server on AWS is not competitive with Microsoft's purchase pricing. Paying almost 10x more is not reasonable. The author points out that ISVs normally have agreements with other ISVs to use their software in test environments for low or no fees. If the test environment needs Windows or SQL Server, you'll have to pay a lot for it at AWS.

One last point, the author wondered if anyone does resource flexing in the cloud. As I pointed out at the beginning of my post, AWS is commonly used for testing because people can scale-up their resource usage prior to release deadlines and when testing at scale. They reduce their resource usage when the need passes. Hence, resource utilization and speed to acquire incremental resources are additional factors to consider.