Our thought was that we could use nodes (in a test scenario only) running different versions to practice upgrades and migrations of databases from one release to the next. Of course, if this works in practice, it would offer less downtime in production upgrades, right (similar to staging a single-node upgrade by installation of software only in advance). _____ From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of David Ballester Sent: Thursday, November 06, 2008 10:59 AM To: mfontana@xxxxxxxxxxx Cc: oracle-l@xxxxxxxxxxxxx Subject: Re: Concurrent Clusterware 2008/11/6 Michael Fontana <mfontana@xxxxxxxxxxx> Is it possible to run both 10g and 11g clusterware on the same node? The documentation only provides upgrade instructions, and seems to imply that an 11g install will fail if it detects existing an existing crs process running. Anyone doing this? Why? Seems that if done, you can expect a lot of unexpected results ( don't care if both are Oracle or a mix of diferent clusterware solutions ). D.