A Windows-based storage speed testing utility from Microsoft: DiskSpd

If you ever need to test storage performance on Windows systems, Microsoft provides an excellent free tool called DiskSpd. It's a small, open-sourced command-line utility that can generate various I/O workloads and report detailed statistics about throughput, latency, and queue depth.

DiskSpd replaces older tools like "sqlio.exe", which many database administrators have used in the past. The syntax is flexible and supports testing local disks, SANs, SMB shares, and even Azure File shares.

Here's a simple example that tests random reads for 30 seconds using a 1 GB test file:

diskspd.exe -b4K -d30 -r -o4 -t2 -W0 -c1G testfile.dat

This runs a 4 KB random read test with two threads and four outstanding I/O operations per thread. The output includes IOPS, throughput in MB/s, and latency percentiles.

DiskSpd can also simulate write operations, mixed workloads, and sequential access patterns. You can specify block sizes, thread counts, test durations, and more. It's extremely flexible for both synthetic benchmarks and storage tuning.

Unlike GUI benchmarking tools, DiskSpd's results are reproducible and scriptable. This is perfect for automation or comparing configurations across servers. If you work with SQL Server or Hyper-V, this is a must-have utility.