My db was upgrades from 220.127.116.11 to 18.104.22.168 som days back. Yesterday we rollback it from 22.214.171.124 to 126.96.36.199.
When i started the applications 11.5.9 and they were up. I tried to login to db usings apps/apps it showing the below error.
ORA-01034: ORACLE not available
ORA-27101: shared memory realm does not exist
HP-UX Error: 2: No such file or directory
That means one of two things. (1) The database hadn't started yet, but will start. Simply retry in a couple minutes. (2) More commonly something caused the memory segment to fail, which didn't get reported by your start up scripts, or your database is offline for maintenance. Sign on as the SYSDBA, issue the manual command to startup. If it still doesn't start, check your database log files for an error.