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Re: Sys and System

From: Chuck Whealton <>
Date: 16 Jul 2006 15:34:04 -0700
Message-ID: <> wrote:
> Hi everyone,
> What is the difference between sys and system? And which one is more
> powerful?
> If I want to use EXP to create a dump file and then use the dump file
> with IMP to recreate the database in another machine, which id should I
> use to do the EXP?
> Regards
> Ujang


There are a number of ways to do this. Here are some of the ways I usually do what you're trying to do. You can use these methods at your own descretion. If anybody sees anything blatently wrong, please speak up.

If using 8i or 9i, you could use RMAN to back the database up, move the RMAN backups on over and then use RMAN to restore them. If using a recovery catalog in the process, I would perform the open/resetlogs while NOT connected to the recovery catalog.

If you're using a recovery catalog and plan to include the cloned database in your RMAN backups, you'll need to use the NID utility to change the database ID as RMAN won't allow duplicate database IDs in the same catalog, which you'll have after an RMAN backup/restore. Note that this requires a 9i (or presumably 10g) home on the system you cloned to.

You could also just do a cold copy and once again, if necessary, use the NID utility to change the duplicate DBID. Once again, requires the NID utility that came with 9i and presumably 10g.

After and open/resetlogs or NID, you should backup your newly cloned database.

I believe another poster mentioned just recreating the database from scratch, the tablespaces and schemas, and importing the data. I've done that before also, using export and import in 8i and 9i - no problems.

Those are some of the ways >I< use. You should ensure whatever you do is acceptable at your company and backup your database before and after anything you choose to do. Ensure your restores are tested.

Another user mentioned some utilities that 10g comes with and I'll certainly defer to them as my 10g experience is limited. But for my own purposes, whenever I need to clone a database, I just use RMAN and if necessary, NID. Occasionally exp/imp.

Good luck...

Charles R. Whealton
Charles Whealton @ Received on Sun Jul 16 2006 - 17:34:04 CDT

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