Re: How many instances are created in the server?

On Apr 13, 8:14 pm, Woody Ling <woodyl..._at_gmail.com> wrote:
> For DB2, I can use 'db2ilist' to list all created instance in the
> server.
>
> Is there any way in oracle to check and display all created instances
> in the server even though they are not started?
>
> Thanks.
> Woody Ling
> Hong Kong

An instance doesn't exist until it is started, since it is a combination of processes and memory structures. It is actually quite a tough general problem to figure out which potential instances may be started on a box, since things may be configured in many ways. If everything were done right, it would be simple, the oratab would show the instances, but as David pointed out, it might not be maintained correctly, and in addition some platforms put it elsewhere than /etc. And some places don't use it at all.

One possible way to figure it out is to look for pfile*.ora and spfile*.ora, but of course, if they exist on a mount point that isn't there when you are looking that won't work either (I can't help it if some sysadmins do weird things!). The more common case as far as I've seen is old and unused things scattered about to really confuse the newbies. Another thing is to look at all .profiles and .logins (and similar files on your environment) for references to ORACLE_HOME, oraenv or coraenv, and see if there is anything in $ORACLE_HOME/dbs or $ORACLE_HOME/network/admin, they may give a clue. look for tnsnames.ora files floating about (including on clients). Also check the docs for OFA, look in those places for trace or alert logs (perhaps ${ORACLE_BASE}/admin/${ORACLE_SID}/*dump/*, though I've seen that not work with a strange $ORACLE_BASE/$ORACLE_HOME test environment, try a find / -name "aler*log"|more)

In addition, there may be Application Server instances.

All we can say is, read the concepts and administration manuals, and know your configuration.

jg

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