2009/12/17 Guillermo Alan Bort <cicciuxdba@xxxxxxxxx>: > Someone once pointed in this list, that having no scheduled downtime is > unrealistic... and it would end up with unscheduled downtime. So I suggest > you reviste that part of the question ^_^ Completely agree with you there. > > As for patches that allow rolling upgrades... well. there aren't that many, > and mostly no CPU allows it (requires startup upgrade, so...) I'd dispute that on the CPU's I think I've doing a rolling apply of every CPU this year. To be fair to Oracle, I think they genuinely have made a bit of an effort in reducing downtime with this. > I'm given to understand that there are some patches that can be applied > online in 11g... but think of it this way: Applying a patch online means > changin a binary or something in the dictionary... that could lead to a > whole lot of trouble and require consistent copies of libraries and > binaries... this is something very hard to accomplish, if at all possible. > > On the other hand, there is no 0 downtime solution with Oracle. There is a > 'very little downtime' solution, which is RAC + DG... which has a lot of > issues still. But still, in the event of the ENTIRE RAC going down, there > would be a downtime, minimal, but downtime at last. > > As mission-critical systems go, not counting custom systems, Oracle RAC + DG > is the best money can buy... the question would be... how much are you > willing to spend... > > A six node RAC with a TAF enabled application would have virtually no > unscheduled downtime, and minimal scheduled downtime (make sure you use > separate homes) even a three or four node version of that would work... > > hth > Alan.- > > -- //www.freelists.org/webpage/oracle-l