[linux-lvm] LVM Snapshots & journal recovery

[Joe Thornber]

On Tue, May 22, 2001 at 03:32:19PM -0600, Peter J. Braam wrote:
<snip>
> 
> But during recovery, LVM cannot possibly know if the whole process of
> copying out the data from the current to the snapshot area completed
> during the previous run. Yes, LVM updates the redirection table first and
> then copies, but, still, you don't know _where exactly_ the writes stopped
> happening and in particular you don't know if the block was copied already
> or not.
>

The snapshot metadata (redirection table) is written *after* the copy.
Data will not hit the origin device until after the copy on write has
completed successfully.

- Joe