pg_basebackup and snapshots

Greetings,

(Moving to -hackers, changing thread title)

* Andres Freund (andres@anarazel.de) wrote:
> Maybe that's looking too far into the future, but I'd like to see
> improvements to pg_basebackup that make it integrate with root requiring
> tooling, to do more efficient base backups. E.g. having pg_basebackup
> handle start/stop backup and WAL handling, but do the actual backup of
> the data via a snapshot mechanism (yes, one needs start/stop backup in
> the general case, for multiple FSs), would be nice.

The challenge with this approach is that you need to drop the 'backup
label' file into place as part of this operation, either by putting it
into the snapshot after it's been taken, or by putting it into the data
directory at restore time.  Of course, you have to keep track of WAL
anyway from the time the snapshots are taken until the restore is done,
so it's certainly possible, as with all of this, it's just somewhat
complicated.

Certainly open to ideas on how to improve this.

Thanks,

Stephen