Using snapshots as quick restore point

Using snapshots as quick restore point

[Robert Pankowecki]

Is it possible to use snapshot as some kind of point in time that i can
go back into? Here is what i would like to do:

* create snapshot
* mount it somewhere (read-write)
* operate on the snapshot, change some files etc...
* revert changes made to the snapshot to its original state with or
without unmounting it.

If not, is there any filesystem that can do that ?

Robert Pankowecki

Re: Using snapshots as quick restore point

[Chris Ball]

Hi,

   > * create snapshot
   > * mount it somewhere (read-write)
   > * operate on the snapshot, change some files etc...
   > * revert changes made to the snapshot to its original state

Make two snapshots instead of one, and only modify one of them?
Because of CoW, new snapshots have very low overhead.

   > with or without unmounting it.

You would have to unmount it if it had any open files.

   > If not, is there any filesystem that can do that ?

I don't know of any filesystem that lets you discard changes to a
snapshot, but I've just described a method for doing so where you
always make a read-only -pristine version of that snapshot and have
tools that base your read-write snapshots on that.

I don't think it would be possible for any filesystem to handle
changing snapshot on a mounted filesystem with files open, so it
makes sense that it's a remount operation.

- Chris.
-- 
Chris Ball   <cjb@laptop.org>
One Laptop Per Child