Fio

Information

fio is one of the preinstalled packages for our r/Techsupport Rescue Media. If you are using this live image, you can skip the installation section.

How to install fio

Refer below for installation instructions if you are not using our live image or want to install it on your own system.

Installing fio

Refer below for installation instructions if you are not using our live image or want to install it on your own system.

Debian / Ubuntu / Linux Mint:

sudo apt update && sudo apt install fio

Fedora / RHEL / CentOS / AlmaLinux:

sudo dnf install fio

Arch / Manjaro / CachyOS:

sudo pacman -Syu fio

Common tests to run

Warning

Running fio on a mounted filesystem or active block device can cause data loss. Always ensure you are targeting the correct device and have backups before running tests!

Mixed read/write test: Real-world read/write-heavy apps.

sudo fio --name=mixed --filename=/dev/nvme0n1 --rw=randrw --bs=4k --rwmixread=70 --iodepth=32 --ioengine=libaio --direct=1 --size=10G --time_based --runtime=60 --group_reporting

Random read test: IOPS for databases.

sudo fio --name=randread --filename=/dev/nvme0n1 --rw=randread --bs=4k --iodepth=128 --ioengine=libaio --direct=1 --size=10G --time_based --runtime=60 --numjobs=4 --group_reporting

Random write test: OLTP workloads.

sudo fio --name=randwrite --filename=/dev/nvme0n1 --rw=randwrite --bs=4k --iodepth=128 --ioengine=libaio --direct=1 --size=10G --time_based --runtime=60 --numjobs=4 --group_reporting

Sequential read test: Max throughput for large files/databases.

sudo fio --name=seqread --filename=/dev/nvme0n1 --rw=read --bs=1M --iodepth=32 --ioengine=libaio --direct=1 --size=10G --time_based --runtime=60 --group_reporting

Sequential write test: Write speed for logs/backups.

sudo fio --name=seqwrite --filename=/dev/nvme0n1 --rw=write --bs=1M --iodepth=32 --ioengine=libaio --direct=1 --size=10G --time_based --runtime=60 --group_reporting

Tip

Adjust --numjobs for multi-queue testing.

Usage guidelines

This is a guide for making your own custom tests. FIO runs via command line or job files (INI-style text files with [global] and [jobname] sections). The general idea usually goes:

• Target a file (filename=testfile) or block device (filename=/dev/sdX – use lsblk to identify).
• Define workload: --rw=read (sequential read), --bs=4k (block size), --size=1G (test size), --runtime=60 (seconds).
• Use --direct=1 for O_DIRECT (bypasses cache), --ioengine=libaio for async I/O, --iodepth=32 (queue depth).

An example would be:

sudo fio --name=test --filename=/tmp/testfile --rw=read --bs=4k --size=1G --numjobs=1 --time_based --runtime=30s --group_reporting

Output shows bandwidth (BW), IOPS, latency. Use --output-format=json for parsing.

Creating custom tests

If you have a dedicated set of tests you want to create for reuse later, you will create a .fio job file (e.g., nano test.fio), then run fio test.fio. The general ideas on the key aspects to focus on are:

• I/O Pattern (rw): read, write, randread, randwrite, randrw, trim, readwrite.
• Block Size (bs): 4k, 64k, 1M; ranges like 4k-64k.
• Engines (ioengine): sync (default), libaio (async POSIX), posixaio, io_uring (modern Linux), mmap, netsplice.
• Other: numjobs (threads), iodepth (queue), size (total data), runtime/time_based, loops (repeats), verify=md5 (check data).
• Advanced: rwmixread=80 (read % in mixed), ramp_time=10s (warmup), stonewall (pause between jobs).

An example job file would look like so:

[global]
ioengine=libaio
direct=1
time_based
runtime=60
group_reporting

[randread]
rw=randread
bs=4k
iodepth=32
size=10G
numjobs=4

You will then run this test file by typing sudo fio test.fio. For more information on how to create a test file, please visit the official FIO documentation hub.