Client access to an Oracle Database may be refused even when Neverfail Heartbeat reports that the Oracle Application status is “Started”.
This may be due to one of the following reasons:
1. The Database has not completed its start up process (may occur just after a switchover or failover)
Depending on the state and size of the database this may take a while. It may be possible for your DBA to optimize the Oracle startup to reduce startup time.
2. The Database may have been shutdown by your DBA (rarely occurs during normal operation).
If a DBA has shut down a database it is usually to perform administrative duties that would be compromised by user access. You should contact your DBA to confirm if a database has been shut down for maintenance.
3. The Database cannot restart due to an Oracle problem (infrequent; may occur just after a switchover or failover).
Use the Oracle Database Control option on the Active machine to review and correct the Oracle Errors.
4. The Database was not restarted after one of the Oracle services failed (very infrequent; may occur during normal operation).
Review the Windows Application Event Log – you will see two events for the “Neverfail Monitor”, with the second one showing that the Oracle Service has been restarted. Use the Oracle Database Control option on the Active machine to review and correct any Oracle Errors and restart the Database.