On Tue, Oct 9, 2018 at 11:25 AM, Andrei Borzenkov <arvidjaar@xxxxxxxxx> wrote: > 09.10.2018 18:52, Chris Murphy пишет: >>> In this case is root/big_file and snapshot/big_file still share the same data? >> >> You'll be left with three files. /big_file and root/big_file will >> share extents, > > How comes they share extents? This requires --reflink, is it default now? Good catch. It's not the default. I meant to write that initially only root/big_file and snapshot/big_file have shared extents And the shared extents are lost when snapshot/big_file is "overwritten" by the copy into snapshot/ >> and snapshot/big_file will have its own extents. You'd >> need to copy with --reflink for snapshot/big_file to have shared >> extents with /big_file - or deduplicate. >> > This still overwrites the whole file in the sense original file content > of "snapshot/big_file" is lost. That new content happens to be identical > and that new content will probably be reflinked does not change the fact > that original file is gone. Agreed. -- Chris Murphy
