Re: copy / move reflink files to new filesystem / or whole fs

["Darrick J. Wong" <djwong@kernel.org>]

On Tue, Jun 15, 2021 at 07:45:59AM +0200, Ralf Groß wrote:
> Hi,
> 
> is there any way to copy or move data between 2 xfs fs with reflinks
> on the same host, so that the data is not rehydrated (I guess cp
> --reflink will not be working)? If this is not possible, would it be
> able to clone the existing fs to a new one and then continue to use
> both?
>
> Background: I've backup data on a 350 TB reflink xfs fs, now a second
> fs will be added to the server and parts of existing data should be
> moved to it. If it's possible to clone the whole fs I could delete
> parts of it afterwards, but copying/moving single directories would be
> easier.

Reflinking (aka data block sharing) can only be performed between files
within a single filesystem.  You could use xfs_copy to clone the fs
which would be faster than dd, though not as fast as targeted copying of
parts of the directory tree as needed.

--D

> 
> Ralf