Linked by Thom Holwerda on Thu 26th Mar 2009 17:07 UTC, submitted by Anil Gulecha
ZFS and unbreakable upgrades were introduced in an earlier article. XercesTech has written a detailed article on how apt-get and zfs join forces to provide a worry-free upgrade experience. "While some operating systems provide the ability to roll back changes, they usually require significant time, or an experienced user with some external repair tools. The goal here is to be instant, if something goes wrong with an upgrade, it should be possible to boot into the old system without running any terminal commands, booting any rescue system or installation disc, or otherwise manually rolling things back."