Azure Speed test using DiskSpd

The decision was made to utilize Azure as IaaS for a large portion of our AX project. We learned some quick lessons in IO speed using Azure right off the bat. I created this quick post to document some of the tools and steps we used to measure IO speed that helped us identify various IO bottlenecks and re-engineer some of our environment settings.

Microsoft released a tool a while backed called DiskSpd. This tool replaced the old tool SQLIO. It is pretty easy to use but will require some tweaking of parameters to get it to simulate various read/write payloads.

100% Reads 8K Blocks

We started off using 100% Read Payloads using 8KB Blocks since SQL Server is organized in 8KB Pages.


You can review the documentation of DiskSpd for details on the various parameters and options.

The initial results were awful. The MB/s were below 10, AvgLat was above 80ms. We contacted Microsoft with our results and they sent us over some build guides to help us maximize performance. After we applied their settings the speed was better but still terrible compared to our On-Prem storage.

We ended up moving some of our DEV Servers to a Azure Data Center that had premium storage. One key take away from the Azure experience is that if you need high performing IO (for SQL Server and such) you will need to use Premium Storage and get ready to spend some cash.

I wrote a PowerShell script that would execute a DiskSpd test every 20 minutes and then store the results in a Database. We had several DEV servers in the project and i wanted to see how the disk performed over several days. Here is the PowerShell



The powershell script calls a real simple Stored Procedure on the SQL Server I am using to store the stats.