On Thu, 2003-07-03 at 08:05, Eric Sammons wrote: > I wanted to get an idea of what others are doing in the way of cloning and > then upgrading their z/VM - z/Linux guests. I am running SuSE Linux 7.x > and will soon be upgrading to SuSE 8. In our Proof of Concept their is a > great desire to share binaries. I; however, can not figure a practical > way of doing this that helps given that all the "system specific" > configurations are in /etc and /etc could and likely will change as a > result of upgrading. Because /etc is system specific it can not be > shared, and because /etc may be impacted by an upgrade of the OS it is not > as straight forward as sharing /usr and then only upgrading the one system > where /usr is the master. > > Is anyone using binary sharing? If so what for and how is it benefiting? > Is it helping in the area of system upgrades?
There are three classes of service upgrades. Ones that only touch the shared DASD (usually just /usr), ones that only touch per-guest DASD, and ones that touch both. The first case is trivial: update the master only (note that you'll still want to have it update a different disk and have an automated tool to repoint your disks at the updated /usr, so everyone always gets a consistent view of the disk). The second case is trivial too: apply the service on each machine. The third case is trickier, and basically involves applying the service to the master, and giving each guest a writable scratch disk to use as /usr while it applies the service. Then you throw away the scratch disk and use the real shared /usr instead (which already has the service applied); repeat for each guest. It's not trivial to set up, but it's not *that* big a deal either, especially since you will need policies and procedures (and scratch disks) in place to let you roll back service anyway. Adam
