Hi Gurus, This seems very common issue but I am confronted with a requirement where we need to have 24x7 availability, no exceptions. There is no way we can have staging server (for patch testing before deploying on the production.) and we need to accommodate software upgrades without a planned downtime. I'm also wondering how shops having 24x7 availability addresses such issues? Since I'm focused solely on Oracle, I'm not aware if any database server allow patching/upgrading without bringing down the server? Is any mainstream database server offer such solution? Thanks, DP.