Re: RMAN Questions: Channels and Restores

"Don Seiler" <don_at_seiler.us> schrieb im Newsbeitrag news:pan.2003.11.07.15.32.30.417995_at_seiler.us...
> I'm working with a test Oracle9i (HPUX) instance and working on practicing
> backups and recovery scenarios. Across reading the references docs on the
> Oracle site and some example RMAN scrips at dbaclick.com, I'm curious as
> to what extra benefit there is to be had in allocating multiple channels
> for a backup to disk, as opposed to just using RMAN's default single disk
> channel.

If you have several CPUs and an i/o system to match then you can serve a faster tape.

> Also just to clarify in my mind, multiple channels does NOT mean multiple
> copies of the backup, right?

Right.

> The oracle doc said that "when backing up to
> disk you can allocate as many channels as necessary for maximum
> throughput." This sounds like allocating extra channels (up to a point)
> will decrease the backup time. Please correct me if I'm wrong.
Yes.

>
> Also a question about restores. I believe that I've seen this on another
> post but I want to be sure in black-and-white. If I want to take a backup
> of my production database and restore it on to a
> test/training/dev/whatever machine, I need to put those backup files in
> the same file path as they were made on the prod machine, and then RMAN
> will automagically know everything it needs to know? Although I still
> have reading to do, I'll risk asking: How will RMAN know? Do I need to
> call RMAN with a param pointing to those backup files? If so, why would
> the files need to be in the same file path (not that it is a problem for
> me anyway)?

In order to copy a database to some other server I'd use the duplicate database functionality. That also takes care of the controlfile.

Lots of Greetings!
Volker Received on Fri Nov 07 2003 - 10:04:26 CST