HCIBench 1.6.2 – Testing vSAN performance

Over the past month or so I’ve been running a number of performance tests on VxRail and vSAN solutions.

HCIBench is a brilliant tool to help end-users understand the type of performance that they can achieve with their vSAN solution.

It’s essentially an automation wrapper around the popular Vdbench tool. Vdbench is an utility specifically created to help engineers and customers generate disk I/O workloads to use for validating storage performance and storage data integrity. Vdbench is a complex beast to run, with lots of different variables that can be configured via CLI… so the HCIBench wrapper helps simplify workload profiles and makes it so much easier to run benchmark tests!!

Please note, HCIBench is a VMware Labs Fling and so there’s limited support available and it shouldn’t be used in production environments (although the latter is just to cover themselves). If I’m honest, the creators of HCIBench are pretty good at replying to comments and feedback!


It’s definitely worth remembering that as a benchmark tool, it can’t quite simulate real-world workloads! However, if you understand how your workload behaves (ie block size, read/write ratio, etc) then you can get pretty close to creating a workload profile that matches your workload (albeit running a test at max. workrate rather than the bursty rate we see in real-life).


HCIbench was updated 2 days ago in response to the recent release of vSphere 6.5u1, and in my opinion is even cooler now that it can utilise the new vSAN Performance Diagnostic feature of vSAN 6.6.1 (API integration with the new Performance Diagnostics part of vSAN Cloud Analytics).

You can now run an HCIBench test and view detailed results of the test in Performance Diagnostics with supporting graphs – you’re able to select a goal for the test based on “Max IOPS”, “Max Throughput” or “Min Latency”, and then get details on potential issues found in the analysed data which you can then use to improve the workload profile you’re using in HCIBench.

Point your browser here for more info:

Note: You need to have Customer Experience Improvement Program(CEIP) and vSAN Performance Service turned on to get this feature enabled