You are quite right. As has been pointed out here recently, the system as a whole may achieve 100% availability by using pervasive redundancy but the individual machines in the system won't. The associated PDF suggests that there may be long lived processes that would be intolerant to any outages due to their inability to save state properly or would exhibit a certain unhappiness with network connections dying. One would suggest that a system administrator designing and implementing a HA environment would make sure that each and every piece of software on each machine could handle a reboot if necessary. While I love the idea of hot updating and while I think this implementation is a fine fine hack worthy of much admiration I would welcome a concrete use case other than, "look I have 5 years, 2 months, 4 hours and 16 minutes uptime".
Comments and public postings are copyrighted by their creators.
Linux is a registered trademark of Linus Torvalds