Thank you all for your responses to my boot snapshot problem but it still exists. . Hugo, you told me how to mount a snapshot. Thank you, that works but you didn't tell me how to boot into it.
Anthony, I really hoped that you had provided the answer using grub but all combinations of your suggestions result in a boot failure with standard error message of unable to mount root because of of wrong fs type etc. I assume that with your suggestion I need a standard fstab entry with default options but it doesn't work even with subvol options. I am always nervous of messing with the MBR so I want to stick with grub. Perhaps this is a fedora problem but I have to say I find it very strange that they tout btrfs as the future, particularly with respect to rollbacks but provide no guide to doing this. I assume it is a combination of grub boot parameters and fstab but nobody seems to know what to do. I am not a techo so I just need simple instructions. Is there any other site, I should be posting this on? Thanks in anticipation On Tue, 2010-11-23 at 00:45 -0600, C Anthony Risinger wrote: > On Mon, Nov 22, 2010 at 10:47 PM, Wenyi Liu <qingshen...@gmail.com> wrote: > > 2010/11/23, david grant <d...@david-grant.com>: > >> I thought I would try btrfs on a new installation of f14. yes, I know > >> its experimental but stable so it seemed to be a good time to try it. > >> I am not sure if I have missed something out of all my searching but am > >> I correct in thinking that currently: > >> I. it is not possible to boot from a snapshot of the operating > >> system and, in particular, the yum snapshots cannot be used for > >> that purpose > > > > Is the Fedora grub support btrfs now? > > In this page http://fedoraproject.org/wiki/Features/SystemRollbackWithBtrfs > > I got the following information: > > (deferred) a patch to grub1 -- on top of the already existing patch to > > support btrfs in grub1 -- to allow selecting between snapshots of the > > boot partition. > > all you need to do is add: > > subvol=<name of the snapshot> > > -- or -- > > subvolid=<id of the snapshot> > > to your kernel boot line (edit in grub on the fly)... however, if > fedora is like archlinux in this respect (brief google search seems to > agree), you will actually need to add this: > > rootflags=subvol=<name of the snapshot> > > where `rootflags` are the mount options passed to the initramfs/root > device. also, you reeeeally don't need grub, whatsoever[1]; in arch, > we use an initramfs hook to perform system rollback by dynamically > modifying the rootflags in accordance with the user's choice: > > http://aur.archlinux.org/packages/mkinitcpio-btrfs/mkinitcpio-btrfs/btrfs_hook > > perhaps someone in fedora can adapt that script... it's rather simple, > and it's MUCH easier and safer than fiddling with grub legacy[1]. > > C Anthony > > [1] note however, that a proper grub2/extlinux solution is ideal to > support kernel-level rollbacks. in the link above, everything is > rolled back except the kernel (residing on /boot... non-btrfs). > though, a kexec solution may be possible. -- 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
