fio review
A free, open-source benchmark for deeply configurable storage I/O workloads.
Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
fio is an open-source I/O workload generator and benchmark tool for storage devices, filesystems, operating-system I/O subsystems, and schedulers. It suits engineers, developers, and advanced users who need to define and repeat detailed storage tests rather than run a general-purpose PC score. Workloads can include sequential reads and writes, random reads and writes, mixed read/write activity, and trim operations. fio supports Linux, Windows, and macOS.
Its main strength is workload depth. Job files use INI-style sections and parameters, while command-line options support automation. A workload can run multiple jobs, threads, processes, and concurrent operations, with configurable I/O engines and queue depths. Results include bandwidth, IOPS, submission latency, completion latency, and total latency. Bandwidth, IOPS, and latency logging add detail for analysis, and output can be produced as normal text, terse CSV, JSON, or JSON+.
fio is free and open source, making it a practical choice when repeatable, customizable storage measurements matter more than a simplified interface. Its breadth across operating systems and its automation features also fit scripted benchmarking and detailed workload comparison. The trade-off is specialization: users looking for a straightforward, broad PC benchmark may find fio too technical or too focused on storage I/O. Choose it for configurable storage workloads, concurrency, queue-depth control, latency analysis, and machine-readable reporting; choose an alternative when the priority is general PC performance coverage or a simpler benchmarking workflow.
fio pros and cons
- Where it wins
- Detailed sequential, random, mixed, and trim workload control
- Measures bandwidth, IOPS, and submission, completion, and total latency
- Runs on Linux, Windows, and macOS with CLI and job-file automation
- Where it doesn't
- Specialized for technical storage I/O benchmarking
- Workloads require configuration through job files or command-line options
- Broader PC benchmarking needs may require a different tool
fio fact sheet, pricing and score →
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