Writing to read-only devices with aufs2
Invisible Ink

© Raoul Fesquet, Fotolia
Add temporary write capability to a read-only device with the stacked filesystem aufs.
Aufs [1] is a stacked filesystem similar to UnionFS [2]. One very common use for aufs is adding "temporary writing" capability to a filesystem residing on read-only media. I use aufs in Knoppix to join read-only data from the compressed Knoppix file (usually located on a CD or DVD) with a read-write filesystem on ramdisk or a USB flash drive. A stacked filesystem creates a stack of existing directories that are "transparent" to the user: Each access to a file is tried for each directory of the stack until it succeeds or the end of the stack is reached.
Even if you aren't building your own Live system, you still might have a practical use for aufs as a means of adding virtual read-write access to files stored on a read-only device. In this article, I describe how to add temporary write capability to a read-only device using aufs.
Gitting Aufs2
Aufs2 comes in two forms: a complete Git-based kernel with aufs2 included and a "standalone" version that contains only the changes that have to be patched into the kernel source.
[...]
Buy Linux Magazine
Subscribe to our Linux Newsletters
Find Linux and Open Source Jobs
Subscribe to our ADMIN Newsletters
Support Our Work
Linux Magazine content is made possible with support from readers like you. Please consider contributing when you’ve found an article to be beneficial.

News
-
Dash to Panel Maintainer Quits
Charles Gagnon has stepped away as maintainer of the popular Dash to Panel Gnome extension.
-
CIQ Releases Security-Hardened Version of Rocky Linux
If you're looking for an enterprise-grade Linux distribution that is hardened for business use, there's a new version of Rocky Linux that's sure to make you and your company happy.
-
Gnome’s Dash to Panel Extension Gets a Massive Update
If you're a fan of the Gnome Dash to Panel extension, you'll be thrilled to hear that a new version has been released with a dock mode.
-
Blender App Makes it to the Big Screen
The animated film "Flow" won the Oscar for Best Animated Feature at the 97th Academy Awards held on March 2, 2025 and Blender was a part of it.
-
Linux Mint Retools the Cinnamon App Launcher
The developers of Linux Mint are working on an improved Cinnamon App Launcher with a better, more accessible UI.
-
New Linux Tool for Security Issues
Seal Security is launching a new solution to automate fixing Linux vulnerabilities.
-
Ubuntu 25.04 Coming Soon
Ubuntu 25.04 (Plucky Puffin) has been given an April release date with many notable updates.
-
Gnome Developers Consider Dropping RPM Support
In a move that might shock a lot of users, the Gnome development team has proposed the idea of going straight up Flatpak.
-
openSUSE Tumbleweed Ditches AppArmor for SELinux
If you're an openSUSE Tumbleweed user, you can expect a major change to the distribution.
-
Plasma 6.3 Now Available
Plasma desktop v6.3 has a couple of pretty nifty tricks up its sleeve.