How to find read and write speed of any storage device in Ubuntu

You do not need to rely on the read and write speeds provided by a hard disk, USB flash drive or SD card manufacturer. It is quite easy to figure out by yourself the sustained read or write speed of any storage device in Ubuntu.

Make sure your storage device is plugged in, has a filesystem and is mounted under Ubuntu. Let us assume it is mounted at /media/my-usb-disk/.

• To find the write speed we write a 100MB file:

$ dd if=/dev/zero of=/media/my-usb-disk/speed-test-file bs=100K count=1k

• To find the read speed we read the 100MB file:

$ dd if=/media/my-usb-disk/speed-test-file of=/dev/null bs=100K count=1k

Remember to delete the temporary file after the test is done:

$ rm /media/my-usb-disk/speed-test-file

Results

Some read-write speeds I found on my devices:

• Internal SSD in Windows notebook: 6.1 GB/s read, 1.9 GB/s write
• Internal SSD in Linux notebook: 2.6 GB/s read, 389 MB/s write
• USB 3.0 harddisk of Windows notebook: 225 MB/s read, 34 MB/s write
• USB 2.0 harddisk of Nvidia Shield accessed as SMB share: 446 KB/s read, 1.2 MB/s write (terrible!)

Tried with: Ubuntu 22.04 LTS