PING[ARC1]: Heartbeat failed to connect to standby ‘dgp’. Error is 1031.

just for short, digged another “circumstance” of oracle operation, in a data guard environment this time. i usually set up standby databases from a rman backup set, clone and adapt the spfile, clone the password file, create a new instance and so on. this works great, no problems so far.

this afternoon however, i got notified that some alert.log of a primary database is packed with messages of the following pattern: