IOzone

iozone is a cross-platform filesystem I/O benchmark tool used to measure the performance of storage systems. It runs a comprehensive suite of tests that exercise file creation, writing, reading, and deletion under varying conditions, such as different file sizes and record sizes, to produce throughput and IOPS metrics. The tests cover both sequential and random operations, including write, read, read-modify-write, and rewrite, with options to separate cached and non-cached results.

The program can report performance as bandwidth (throughput in KB/s or MB/s) and detailed curves showing how performance changes with file size and record size. It supports testing across local disks, network file systems, and memory-based storage, and is designed to operate on a wide range of operating systems, including Unix-like systems, Windows, and macOS.

iozone is typically run from the command line and is portable across platforms. Users configure tests with a variety of options, such as the number and size of files, the record size, and the total data set size. It is distributed as open-source software, with binaries or source code available for download, and is commonly used in storage performance analysis, vendor validation, and capacity planning to compare devices, filesystems, or kernel configurations.

Because results are sensitive to system caching, kernel parameters, and hardware characteristics, iozone results are most meaningful when used to compare similar setups or to track relative changes rather than as absolute measurements.