Re: hierarchical, tree-like structure of snapshots

[Andrei Borzenkov <arvidjaar@gmail.com>]

31.12.2020 21:19, john terragon пишет:
> On Thu, Dec 31, 2020 at 6:28 PM Zygo Blaxell
> <ce3g8jdj@umail.furryterror.org> wrote:
> 
>>
>> I think your confusion is that you are thinking of these as a tree.
>> There is no tree, each subvol is an equal peer in the filesystem.
>>
>> "send -p A B" just walks over subvol A and B and sends a diff of the
>> parts of B not in A.  You can pick any subvol with -p as long as it's
>> read-only and present on the receiving side.  Obviously it's much more
>> efficient if the two subvols have a lot of shared extents (e.g. because
>> B and A were both snapshots made at different times of some other subvol
>> C), but this is not required.
> 
> Can you really use ANY subvol to use with -p. Because if I
> 
> 1) create a subvol X
> 2) create a subvol W with the exact same content of X (but created
> independently)

How exactly you create subvolume with the same content? There are many
possible interpretations.

> 3) do a RO snap X_RO of X
> 4) do a RO snap W_RO of W
> 5) send W_RO to the other FS

Show actual command please.

> 6) send -p W_RO X_RO to the other FS
> 

Again show full command please. Which include also receive command.

> I get this:
> 
> At subvol X_RO
> At snapshot X_RO
> ERROR: chown o257-1648413-0 failed: No such file or directory
> 

You get where? On source, on destination?

> any idea?
>