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Overlay f.s. instead of aufs

September 04, 2016 — BarryK
The layered filesystem Aufs is great, it underpins the architecture of Puppy linux, for frugal installs, etc. Aufs superceded the much older and now defunct Unionfs.

Aufs is available as a patch for the Linux kernel, however something else called Overlay fs made it into the official kernel source. Overlay is not as capable as Aufs.

Currently with "QuickyPi", I am using the standard pre-compiled kernel (right now, using 4.4.19), which does not have Aufs, only Overlay.
Note, the kernels compiled for puppies, at least as far as I know, do not have Overlay enabled, so you can't use it, only Aufs -- ditto for Quirky prior to now.

I want to change over to using Overlay in Quirky. The first step, is I want to run woofQ from a Pi2 or Pi3, with only Overlay available. The scripts '2createpackages' and '3builddistro' make use of Aufs during build of the distro, so I have modified those scripts to use Overlay, if the kernel supports it.

Later on, I will have to look at frugal install of Quirky, which currently uses Aufs.

Note, the reason that I am running woofQ in the Pi, is to do a native build of the Quirky distro. This has certain advantages, such as being able to chroot into sandbox3/rootfs-complete (which 3builddistro does in a few places) -- otherwise, 3builddistro does a "cross build", which delays certain operations until the Quirky distro is booted on a Pi -- resulting in a very slow first bootup.

Tags: linux