Oracle Database unavailable after machine restart

Question

I have a dedicated machine where I have installed Oracle Database 11.2.0.1.0 under Oracle Linux 6. It worked fine until today, when I had to shutdown the machine for physical relocation. Much to my surprise, when I have restarted the machine, EM wasn't available. Then I realized I could no longer remotely connect to the Database. Then I found out that the listener was down. Then I tried starting the listener, it said that no clients are supported. Then I tried to manually start the DB from sqlplus, I could not even log in to it. Then I ran dbca, which cried about EM not being secure. Then I found out that the emkey.ora was missing (and as a newbie, I hadn't made a backup).
I spent 3 hours trying to figure out how to bring the DB online; I'm afraid I ran out of solutions. Right now I am rebuilding the whole EM Repository using dbca and hope for the best.
Update: dbca finished with no errors. I can now connect with sqlplus and see that all data is there. However, EM still doesn't properly connect. I am getting "Enterprise Manager is not able to connect to the database instance". However, state of components lists:
- Database Instance: Open
- Listener status: UP
- Agent connection to Instance: Succeeded
I can't figure out why EM won't connect. I have this feeling it's a listener misconfiguration, however netca is very limited, just a next-next-next thing.
My listener.ora is below:
SID_LIST_LISTENER =
(SID_LIST =
(SID_DESC =
(GLOBAL_DBNAME = eburlacu)
(ORACLE_HOME = /oracledb/product/11.2.0/dbhome_1)
(SID_NAME = eburlacu)
LISTENER =
(DESCRIPTION_LIST =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = eburlacu-server.ro.oracle.com)(PORT = 1521))
ADR_BASE_LISTENER = /oracledb
SUBSCRIBE_FOR_NODE_DOWN_EVENT_LISTENER = OFF
...And why is EM using port 5500?
LE: I can now remotely connect to the Database from a different machine, using Oracle SQL Developer, so the listener seems to be working well, after all. I'm confused now...
Edited by: EduardB on Sep 28, 2012 3:24 PM

Answer 1

Thank you for the response. It makes some sense, however I wouldn't have expected the Oracle DB to be so se sensitive to a simple machine move.
The network configuration hasn't changed a bit. I am in the same network, I have the same IP (it's a static IP and a static DNS hostname which was granted to this machine specifically). I just changed floors.
I never touched the EM environment. All I did was:
1. Installed Oracle Database.
2. Added a schema (basically created a new user).
3. Allowed SQL Developer through the firewall.
4. Remotely connected with SQL Developer and created tables and functions, all basic SQL work, nothing fancy.
The restarts were simply for testing purposes (does it still start as expected? Are there warnings, error messages?). Two restarts were performed to re-arange some wiring, again nothing fancy.
I am just a newbie doing some learning and gaining some hands-on experience (after taking Linux and SQL classes). The Oracle Database 11g Administration Workshops are scheduled for 2013 but in the meanwhile I am trying to understand why could my installation mess up so badly with no outside interaction.
What would your advice be in this situation? Reinstall everything under OEL5 + 11.2.0.1.0? Reinstall OEL6 with clean 11.2.0.3.0 installation?
Note: my first priority at this moment is hands-on experience with SQL. Since both sql*plus and Oracle SQL Developer can connect and work fine, should I simply stop bothering with EM for the moment and let it limp until I attend the Administration Workshops? I have almost half a million records in the DB but my SQL statements (saved on a different machine) can re-generate all the data in about 1h or so, so it's not a big deal if I wipe everything.