Hey Tom On Thu, Oct 25, 2012 at 4:02 PM, Tom Gundersen <teg@xxxxxxx> wrote: > On Thu, Oct 25, 2012 at 3:50 PM, Leonidas Spyropoulos > <artafinde@xxxxxxxxx> wrote: >> Archlinux is supporting btrfs for root filesystem some time now. Have any >> work or thoughts been done for supporting snapshots before update packages? >> This way you can keep record of what's happening to your system and easily >> rollback if something breaks. >> I know Fedora and Suse (if not mistaken) supports that with their package >> managers. > > I put together a proof-of-concept a while back for doing something > like this. It "worked", but was nowhere near ready for public > consumption, so I never posted it anywhere. > Would you be able to share it? > What I thought would be nice was the ability for an upgrade to take > effect on the next reboot without touching the running system. No need > to integrate with pacman, a wrapper in bash would do. > > It went something like this (assuming / is on btrfs): > > create a new subvolume as a snapshot of / > mount the new subvolume on /mnt/ > pacman -Syu --root=/mnt > mark the new subvolume as the default one > > This means the current rootfs is not touched at all during the > upgrade. However, next time the rootfs is remounted (i.e., on the next > reboot) you will get the upgraded system. Moreover, if something went > pear shaped, the subvolume of your old system should still be around > which you can boot into with the right kernel parameter. > > Obviously any changes you do to the rootfs after creating the snapshot > will be lost on the next reboot, so some care must be taken to make > sure you know what you are doing :-) (it might be reasonable to only > allow this if the rootfs is mounte read-only). > > Cheers, > > Tom There is an interesting conversation in btrfs maling list happening now : http://comments.gmane.org/gmane.comp.file-systems.btrfs/20738 -- Caution: breathing may be hazardous to your health. #include <stdio.h> int main(){printf("%s","\x4c\x65\x6f\x6e\x69\x64\x61\x73");}
