[Networker] Questions on Oracle RMAN channels with NetWorker?

Hi,

We're very confused here about this concept of "channels", as used inOracle RMAN scripts, and how this effects NetWorker, and we're hopingsomeone can enlighten us. We have NetWorker 7.2.2 on a Solaris 9 serverwith the NMO license installed. We're using Oracle 10g on the clientmachine which is also running NetWorker 7.2.2 client and has the NMO 4.2software installed. We're planning to test backing up a test database.

We've read through the Legato Admin. guide for NMO multiplatformversion, but we're unclear exactly how a channel effects the backups.In other words, is a channel purely an Oracle thing, or does it alsoinfluence how NetWorker will in turn behave? Is it similar to a savestream or a session? I'm unclear if it makes sense to associate anOracle backup with a normal save set stream but just asking if there'sany correlation in the terminology. Let's say I set my RMAN script touse two channels rather than one. Does this translate somehow to sending2 streams to the NetWorker tape device on the other end? Or does itstill send a single save stream as far as NetWorker is concerned, butthe dual channels remains purely an Oracle thing?

1. Why would increasing the number of channels be beneficial and whatare the justifications for doing this?

2. If we're only backing up one database, does more than one channelmake sense?

3. If, for example, you set the RMAN script to use two channels, willthis require two tapes on the NetWorker end?

4. Does using multi-channels somehow split the Oracle backup into morethan one stream?


Would greatly appreciate any clarification on this.

Bhaskar

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