On 10/3/07, Dave Miner <Dave.Miner at sun.com> wrote: > Brandorr wrote: > > If this is the case, we may want to consider alternate options for > > rollback, as there are applications where one may not want to use ZFS > > as the root filesystem. (Yes there are some). :) > > > > Care to be specific about what you think those are? We've been fairly > explicit all along that ZFS was the only option we were planning to > support installing to, and that's been met with little negative comment, > so I'd like to understand what requirements you have in mind.
Not the first time I've mentioned this, but zfs root doesn't exist even as an option in a current production release. I expect corporate IT departments would wish to see a one-version overlap where zfs and ufs were both options; a caution that's understandable given some negative experiences in the past with changes to the nature of the root filesystem. Upgrading systems can't do an in-place switch from ufs to zfs either. > And can you be specific about the rollback you're asking about? I see something like a snapshot being a useful place to fall back to if applying a patch proves fatal. In 15 years of actively managing hundreds of systems I've seen only one case where that might be useful, and that was a case where Sun released a patch incorrectly (it had a mutual dependency on another patch which wasn't released - and the correct solution there would have been to merge the patches anyway). The downside to going back in time to get to the state you were in before a bad operation also discards all the subsequent changes. There's room for both undoing individual changes and rolling back to a known point of stability. -- -Peter Tribble http://www.petertribble.co.uk/ - http://ptribble.blogspot.com/
