Li Li, In current versions, JUST RAC alone can not provide the 24x7 availability. You need to have the combination of RAC+Dataguard (logical) to have REAL 24x7 availability. Also not all patches/upgrades are 'rolling upgrade' capable. Have a look at this presentation to undertand the issues in rolling upgrade. http://www.oracle.com/technology/deploy/availability/pdf/oow06/S281209_To.pdf -Gopal On 9/10/07, Li Li <litanli@xxxxxxxxx> wrote: > Hi, All, > > I recently patched our 2-node RAC (10.2.0.2 on RHEL AS 4 update 4) to > 10.2.0.3. I got the impression that you can do rolling upgrade in a RAC > environment, until I dig into the patch installation document and found out > that you can do rolling upgrade on the clusterware part but not on the RAC > database part. Fortunately we can afford the service to be down for a couple > of hours. > > My question is: is there a way to keep your RAC database up while you patch > it? RAC itself doesn't really provide 24x7 High Availability? Any comments? > > Thanks, > -Li -- Best Regards, K Gopalakrishnan Co-Author: Oracle Wait Interface, Oracle Press 2004 http://www.amazon.com/exec/obidos/tg/detail/-/007222729X/ Author: Oracle Database 10g RAC Handbook, Oracle Press 2006 http://www.amazon.com/gp/product/007146509X/