"There is no ideal software, it always has bugs. Minor, major or security issues will always exist and modern operating systems need to deal with this fact. What if any software which user installs had a capability to rollback to previously known successful point and operation itself would take no time? What if developer or user has a tool which could checkpoint operating system and capability to revert changes in no time? This is possible if we will marry two great technologies: ZFS and Debian APT. Both technologies now part of Nexenta Operating System which is core foundation for its derivative distributions. Meet apt-clone. The tool which integrates with the NexentaCP system, keeps track of upgrade checkpoints and allows to create/destroy/edit checkpoints by request."