Hi I am configuring Dataguard for a customer and have an issue with the switchover not being smooth The configuration is as follows Unix AIX 5.2 Oracle 9.2.0.5 I have a primary and a single standby instance ellprd and elldrc located on separate servers CREATE CONFIGURATION 'egat' AS PRIMARY SITE IS 'mmmprd' RESOURCE IS 'mmmprd_db' HOSTNAME IS 'mmmprddbs' INSTANCE NAME IS 'ellprd' SERVICE NAME IS 'ellprd' SITE IS MAINTAINED AS PHYSICAL; CREATE SITE 'mmmdrc' RESOURCE IS 'mmmdrc_db' HOSTNAME IS 'mmmdrcdbs' INSTANCE NAME IS 'elldrc' SERVICE NAME IS 'elldrc' SITE IS MAINTAINED AS PHYSICAL; When i did the switchover from mmmprd to mmmdrc it seemed to work correctly but when I then tried to swich then back I get the following in dgmgrl DGMGRL> switchover to mmmprd; Performing switchover NOW. Please wait... Operation requires restart of site "mmmdrc" Operation requires restart of site "mmmprd" Shutting down site mmmdrc... Unable to connect to database ORA-12523: TNS:listener could not find instance appropriate for the client connection Failed. You are no longer connected to ORACLE Please connect again. Unable to shut down mmmdrc You must restart site "mmmdrc" manually. You must restart site "mmmprd" manually. Switchover succeeded. New primary is "mmmprd" I then had to restart both intances to get DGbroker to report the configuration was running ok. Any ideas as to what might cause this Cheers Peter -- //www.freelists.org/webpage/oracle-l