suggestion: rescue boot extension

Jon Masters jonathan at
Wed Jun 2 21:14:23 UTC 2010

On Wed, 2010-06-02 at 16:04 -0500, Michael Cronenworth wrote:
> Eric Sandeen wrote:
> > Is it better to have a separate volume for this, or to just have a sort
> > of rescue initramfs ...?
> >
> > Seems like the latter is more flexible but then I'm no boot process wizard.
> Good suggestion.
> Another one: What about LVM snapshots? and/or btrfs snapshots?

This is already done. But it's very coarse. You get to unwind (possibly)
a lot of stuff, and may not reboot the moment you finish the update. You
also need to have /home on a separate volume, etc. etc. It's great, but
it's not always what you need. So my suggestion is tangential to that.

> Either way would be less wasteful than a whole partition that would be 
> obsolete in a few weeks and may or may not have to deal with byte 
> growing pains if the initial size is too small years down the road.

An initramfs is fine. I wasn't literally saying the only option was to
keep a spare physical partition around. I was thinking that, if it were
a volume, it would be an LVM volume that could be resized later. But I
think the easiest option for now is simply a rescue initramfs on
the /boot volume, and I suppose I see the point now about making a
bigger /boot volume if this happens. That does make sense. This would be
something you could choose not to have installed anyway IMO.

> Another scenario: Your Fedora 14 rescue boot partition was built against 
> kernel 2.6.34, but the root file system of your Fedora 18 installation 
> is of a new experimental file system only found in kernel 2.6.38. The 
> rescue partition is wasted space at this point.

When are we going to have a situation in which Fedora ships F14 with a
new filesystem that works with Anaconda (and therefore a rescue image)
to get installed, but doesn't work after the fact? Maybe you copied and
created this by hand, but in that case you get to keep both pieces when
it breaks. I'm talking about out-of-the box regular user issues :)


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