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This functionality has been in OpenSolaris for quite some time now. It really rocks hard. Make a safe quick rollback in seconds. Awesome. I can really understand why Fedora wants that functionality.
Does OpenSolaris offer package management integration with ZFS so that if a update fails, you can rollback? I am aware a Debian variant of OpenSolaris does that but does OpenSolaris itself do that?
Yes it does.