On Jan 28, 2014, at 12:45 PM, KC <impacto...@googlemail.com> wrote: > On 27/01/14 19:44, Chris Murphy wrote: >> >> On Jan 27, 2014, at 6:53 AM, KC <impacto...@googlemail.com> wrote: >>> >>> 3. If I make a snapshot of / and there are some separate partitions mounted >>> under /mnt/ or /home/, will snapshot skip them? >> >> A snapshot of a subvolume only snapshots that subvolume, not other >> subvolumes contained in it or other partitions/file systems. >> > > Excellent, thank you. > > If currently my /home is just a folder on the / subvolume, is there any way > to promote existing /home to a subvolume status so that if I take a snapshot > of /, the /home gets skipped?
Multiple ways. I think the easiest is for the subvolumes to be at the top level of the Btrfs volume, and mount them where you want with fstab. So for example on Fedora 20 my top level subvolumes are: boot root home root is mounted at / using mount option subvol=root boot is mounted at /boot using mount option subvol=boot home is mounted at /home using mount option subvol=home I've also decided to put systemd-journals on a separate subvolume: journald is mounted at /var/log/journal using mount option subvol=journald That way I can snapshot root, and rollback but have a persistent journal rather than a snapshot specific journal. Of course /home is also persistent because I don't roll it back. You could also rename /home, create a subvolume home within current subvolume root, then move the files from directory /home_old to the subvolume /home. Now when you snapshot rootfs, /home isn't snapshot. In this case you don't need to separately mount the home subvolume because it's available as if it were a directory. It's an organizational thing I don't know that there's a right or wrong here. One thing that came up recently on the Fedora devel list though, with respect to roofs snapshots available in the mounted fs hierarchy, is that an old rootfs snapshot could contain vulnerabilities. So two ways to handle it are to keep snapshots in the top level of the fs outside of the mounted fs hierarchy (only mount it as needed when taking snapshots); and/or mount that snapshots subvolume with noexec or nosuid mount option. That way its executables aren't root executable. Chris Murphy -- 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
