Am Sun, 28 Aug 2016 17:41:22 -0400 schrieb james harvey <jamespharve...@gmail.com>:
> On Sun, Aug 28, 2016 at 12:15 PM, Oliver Freyermuth > <o.freyerm...@googlemail.com> wrote: > > For me, this means I have to stay with rsync backups, which are > > sadly incomplete since special FS attrs like "C" for nocow are not > > backed up. > > Should be able to make a script that creates a textfile with lsattr > for every file. Then either just leave that file as part of the > backup in case it's needed some day, or making a corresponding script > on the backup machine to restore those. The problem with this idea is that chattr +C will only work on empty files, so it needs to be applied in the "middle", read: upon creating the file and before filling it with content. It would be possible to let a script first create empty files according to this list and then use "rsync --no-whole-file --inplace" so it will build upon the empty files instead of its usual behavior to create files temporarily and then rename them into place. I'd recommend to use these options anyways if writing to btrfs snapshots to take advantage of shared extents. Apparently rsync cannot handle sparse files in this mode (tho there should be a patch to make this possible by using the hole-punching feature of newer kernels but it makes the rsync protocol incompatible to unpatched versions AFAIR). I think borgbackup suffers from the same problem. While in latest version it seems to support attrs, it does apply them after filling the files with contents (as most programs do, also attributes like mtime, owner etc are applied after closing the written file, for obvious reasons). This simply doesn't work for +C on btrfs. -- Regards, Kai Replies to list-only preferred. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
