[Merge] livecd-rootfs:xnox/mksquashfs-zstd into livecd-rootfs:ubuntu/master

[Michael Hudson-Doyle]

> On Thu, 24 Aug 2023, 04:02 Michael Hudson-Doyle, <
> mp+449608 at code.launchpad.net> wrote:
> 
> > is it possible to quantify the size and speed changes for this?
> >
> 
> I haven't uploaded this into a PPA and have not rebuilt the .iso nor
> measured the difference.

OK I did that:

https://launchpad.net/~mwhudson/+livefs/ubuntu/mantic/test/+build/485752 (with change)
https://launchpad.net/~mwhudson/+livefs/ubuntu/mantic/test/+build/485753 (without)

The size change seems pretty minor, on the order of a couple of percent larger.

> One can edit squashfs out of band, by unsquashfs them / mksquashfs with
> these options.
> 
> Speed changes - one needs to have reliable way to measure that, but for
> example time to complete autoinstall should be a good ballpark.

Haven't tested this yet.

> 
> 
> 
> > Support for this compression method has been in Ubuntu kernels for quite a
> > while, right?
> 
> 
> Something like v4.14 kernel, but userspace tooling landed like an lts
> release later, and I think zstd build dep was not added immediately. But
> like bionic or focal have everything.
> 
> Obviously these squashfses are going to be mounted by the mantic kernel
> > "for real" but it would be a bit annoying if the jammy kernel could not
> > mount them.
> >
> 
> Mounting with kernel goes back longer than unsquashfs / fuse-squash.

I suspected as much. Thanks.

-- 
https://code.launchpad.net/~ubuntu-core-dev/livecd-rootfs/+git/livecd-rootfs/+merge/449608
Your team Ubuntu Core Development Team is requested to review the proposed merge of livecd-rootfs:xnox/mksquashfs-zstd into livecd-rootfs:ubuntu/master.