Boot from LVM snapshot

[Scott Gifford]

Hello,

I am trying out GRUB 2 with LVM for some Ubuntu 12 (Precise Pangolin) workstations in a medical environment, where it's important that the machines have good availability.  They will also be connected to the Internet, so it's important that they stay updated as well.  LVM seems like a good fit for this; we can take an LVM snapshot, apply updates, and if anything goes wrong users can go back to the snapshot until the problem can be fixed.

I currently have this working as long as the user only wants to boot from the original image.  GRUB 2 and LVM work together nicely, and to roll back I can merge the changes from the snapshot back into the original image.

I think it would be easier to let the users boot directly from an LVM snapshot, but GRUB 2 doesn't seem to recognize the snapshots at all.  When I try to use tab-completion for the device it doesn't list them, and if I set a snapshot volume to my root, trying to list files with "ls" gives an error.

I was wondering if it is possible for GRUB2 to boot from an LVM snapshot?

Also, the various Ubuntu probing tools detect the LVM snapshots and add them to my boot menu, with incorrect options that cause them all to boot from the original volume.  Is that something that might be appropriate for that list?  Or does it sound Ubuntu-specific?

This is with a nightly build of Ubuntu 12.04 (it will be the next LTS version by the time these workstations go live), which contains grub version 1.99-14ubuntu2.

Please CC me on any responses, I'm not subscribed to the list (the GRUB mailing list page says it is not necessary, but please let me know if I should subscribe anyways).

Thanks!

-----Scott.