I've been playing around with a RAC system (10.1.0.4 on RedHat AS3), and managed to crash it(no problem, I'm trying to see what can go wrong). It was probably due to a corrupted Registry file (does ocrconfig -import work?). On trying to export and then import a Registry file, then restart CRS, one of our nodes removed itself (no longer visible from the network. Probable crash). When our SysAdm went down to look, he said Oracle had 'halt'ed the server. All the doc I have seen talks about 'reboot' under certain conditions, but I have never seen a halt (or shutdown) mentioned anywhere. Has anyone else seen (or seen documentation of) this behavior? Henry