I'm not sure I could fully understand the desired achievement but it
sounds like (or this would be an example of selective perception) it's
somehow related with "creating reproducible snapshots"
(https://unix.stackexchange.com/q/462451/65781), no?
Chris Murphy <li...@colorremedies.com>, 14 Eki 2018 Paz, 02:05
tarihinde şunu yazdı:
>
> On Sat, Oct 13, 2018 at 4:28 PM, Chris Murphy <li...@colorremedies.com> wrote:
> > Is it practical and desirable to make Btrfs based OS installation
> > images reproducible? Or is Btrfs simply too complex and
> > non-deterministic? [1]
> >
> > The main three problems with Btrfs right now for reproducibility are:
> > a. many objects have uuids other than the volume uuid; and mkfs only
> > lets us set the volume uuid
> > b. atime, ctime, mtime, otime; and no way to make them all the same
> > c. non-deterministic allocation of file extents, compression, inode
> > assignment, logical and physical address allocation
>
> d. generation, just pick a consistent default because the entire image
> is made with mkfs and then never rw mounted so it's not a problem
>
> > - Possibly disallow subvolumes and snapshots
>
> There's no actual mechanism to do either of these with mkfs, so it's
> not a problem. And if a sprout is created, it's fine for newly created
> subvolumes to follow the usual behavior of having unique UUID and
> incrementing generation. Thing is, the sprout will inherit the seeds
> preset chunk uuid, which while it shouldn't cause a problem is a kind
> of violation of uuid uniqueness; but ultimately I'm not sure how big
> of a problem it is for such uuids to spread.
>
>
>
> --
> Chris Murphy
