Creating Second Instance (UNIX)

[kburrows]

New to Oracle and am looking for some advice on creating a second instance.

[pwoneill]

By second instance do you just mean another database (to use for testing, whatever) on the same machine?

If so the steps arefairly straightforward and easy but go to technet, and under the administrators guide you'll see steps for creating a new database. read those, follow them, make mistakes, figure out what went wrong, and you'll learn about it.

If you're talking about something more advanced, replication, parallel servers, whatever, i would also have to point you to the technet server docs because I don't have much experience in them yet :)

If you're using 8i, the server docs link is [url]http://technet.oracle.com/doc/oracle8i_816/server.816/index.htm[/url] You'll need a free technet registration.

[kburrows]

thank you, I will check that out.

[tamilselvan]

Increase the parameters in /etc/system w.r.t Oracle.
Like SHMMAX etc..

[chobo]

Thing to be considered(brief advise).

1. in init.ora
'process' parameter needs to be set correctly to start up a new instance.
(or set semsys:seminfo_semmns in /etc/system )

2. Don't forget to put a new instance name in oratab file.
3. If possinle, OFA structure....
4. Before start up a new instance, set ORACLE_SID pointing to a new Instance name.
.......

Good Luck..

[kburrows]

Alright, I have gotten more information about this second instance. They will have separate files.

I have an 8.0.5 instance, database running on a server. I will need to create another instance, database with Oracle 8.1.6. Is it possible with two different versions? Does anyone have a checklist for this process.

Thanks in advance
Kathy

[sambavan]

Yes, it is possible. By now you would have a rough idea of how many processes that you are going to have on the new instance. Go to /etc/system and update the SIMMNS and SEMMAX. This is available under oracle installation documentation pg 2.4 - 2.6. Refer that for detail.

SEMMNS = SUM(all_process) + (2 * MAX(all_process) + (#of instances *3)

eg:

SID= A PROCESSES=10
SID= B PROCESSES=20
SID= C PROCESSES=30

SEMMNS = 10+20+(30*2)+(3*10) =120 or more

When you are about to create the database, set your ORACLE_BASE, ORACLE_HOME and LD_LIBRARY_PATH, CLASSPATH and etc to point to the new 8.1.6 installation directory. Then go ahead and call the dbassist, to create a new instance on the system. At this point, if you already have the oratab file, and other datafiles, Iwould advice you to take a backup, to be on the safer side.

Then if you are going to choose the default installation, then the files are created under OFA (oracle flexible archetecture)

$ORACLE_BASE/admin/<SID>/udump/
bdump/
cdump/
pfile/
arc/

$ORACLE_BASE/oradata/<SID>/ *.dbf
*.ctl

As long as you don't use the same names, to name both your instances, you should be filen. If you are going to use the custom installation option, then you can direct where to put the datafiles, logfiles and etc.

Once this is done the tnsnames.ora and listener.ora files are updated for the perticular, version of oracle. If you want to be able to invoke the other instances, from this installation then, you would have to update the tnsnames.ora files on your server and client.

Once after doing the installation, go to the directory

/var/opt/oracle/ and update your oratab file. Mostly you would have to change the N to Y such that it would allow the instance to be shut down and started up during the system shutdown and boot times.

I hope this would help you.

Good luck,
Sam