Re: ISO image: to xz or not to xz?

[Vagrant Cascadian <vagrant@debian.org>]

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On 2021-05-03, Leo Famulari wrote:
> On Mon, May 03, 2021 at 01:47:02PM -0300, Alexandre Oliva wrote:
>> Indeed, install ISOs normally hold already-compressed filesystems or
>> files, so recompressing the .iso doesn't gain much if at all.
>
> To quote the introductory message of this thread:
>
> "The xz-compressed image is 23% smaller, which is not negligible."

Well, the suggestion to use squashfs does bear merit; it would require
having some type of writeable filesystem on top, such as using overlay
fs to mount the installer rootfs with squashfs for the readonly bits,
and tmpfs for the writeable bits.

As a bonus, using a tmpfs overlay would solve the issue brought up
recently by someone who tried using the same installer image multiple
times, and /gnu/store and /var/guix got out of sync due to the cow-store
only writing to the newly installed system, so that the second install
failed.

Another angle might be to use a compressable but writeable filesystem
(btrfs?).

Obviously, it requires someone to do the work to get there!


live well,
  vagrant

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