NAME

fsx — File System eXerciser

SYNOPSIS

DESCRIPTION

The fsx utility tests file system I/O routines for correctness, with random input. It generates a pseudorandom sequence of file modifications and applies them to a file on the file system under test. On every read, it verifies the expected data. It's highly configurable, and the test sequence is 100% reproducible according to a seed value. If a failure is detected, fsx will log the most recent operations and write the expected file contents to FILENAME.fsxgood.

The options are as follows:

-b OPNUM

Begin real I/O at operation number OPNUM. Previous operations will be simulated, and their cumulative effect written to the file just before real I/O starts.

-h, --help

Print usage information.

-f PATH

Load configuration from PATH. The configuration file describes the types of operations that fsx will issue, whereas the other operations describe how fsx will issue them. Generally the user should customize the configuration file for each file system of interest. See the example configuration file for documentation of its contents.

-m FROM:TO

Monitor operations within the byte range [FROM,TO). All operations in this range will be logged at the LOG_WARN log level.

-N NUMOPS

Terminate after processing NUMOPS operations. If this option is not specified, fsx will run until interrupted or a failure is detected.

-q, --quiet

Decrease verbosity. This option may be specified up to two times.

-P DIRPATH

On failure, save artifacts to the directory named by DIRPATH.

-S SEED

Seed the random number generator with this value. By default, fsx will select a seed pseudorandomly, and log it to stderr.

-V, --version

Print the program's version.

-v, --verbose

Increase logging verbosity. This option may be specified up to three times.

EXIT STATUS

The fsx utility exits 0 on success, and >0 if an error occurs.

HISTORY

The first version of fsx was written in C at Apple Computer, beginning in 1998, by Avadis Tevanian Jr. It was imported into FreeBSD 5.0 by Jordan Hubbard <jkh@FreeBSD.org>, but only as a development tool. It was never installed as part of any release. It's had occasional enhancements since then.

fsx was independently imported into Linux in 2001 by user robbiew, and has occasionally merged in features from the FreeBSD version.

A tool by the same name was included in DEC Unix 4.0, but I don't think it shared any code.

This version is a full rewrite in Rust, by Alan Somers <asomers@FreeBSD.org>.