Fio is short for Flexible IO, a versatile IO workload generator. Back in 2005, Jens Axboe, the backbone behind and author of the IO stack in the Linux kernel, was weary of constantly writing one-off test programs to benchmark or verify changes to the Linux IO subsystem. As a result, fio was born to make the job a lot easier. It was flexible enough to allow detailed workload setups, and it contained the necessary reporting to make sense of the data at completion. Jens continued working on fio when he joined Oracle and, later, Fusion-io. Today, the fio community of users is active and engaged in development, and consequently they continually develop fio and implement new features. Greater than 100 people have contributed to fio, and many have done so several times. Thanks to this commitment, a new version of fio is released roughly every 4-6 weeks, and fio is widely used as an industry standard benchmark, stress testing tool, and for IO verification purposes.