Networker

Re: [Networker] Questions on Oracle RMAN channels with NetWorker?

2006-08-22 18:51:11
Subject: Re: [Networker] Questions on Oracle RMAN channels with NetWorker?
From: Matthew Huff <mhuff AT OX DOT COM>
To: NETWORKER AT LISTSERV.TEMPLE DOT EDU
Date: Tue, 22 Aug 2006 18:42:17 -0400
> it similar to a save stream or a session? 
 
Yes, it's a session.
 
> 1. Why would increasing the number of channels be beneficial and what are the 
> justifications for doing this?

Parellelization. More channels the faster, until you overload your client, 
server or both. Tuning is recommended.

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

Yes. Having more channels produces more sessions, which reduce backup time

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

No, only one tape is required. One of Legato's strengths is the ability to 
multi-stream backups to a tape. This keeps tapes running at full speed and 
limits back-hitching.


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

Exactly.

________________________________

From: Legato NetWorker discussion on behalf of Bhaskar Mylavarapu
Sent: Tue 8/22/2006 6:07 PM
To: NETWORKER AT LISTSERV.TEMPLE DOT EDU
Subject: [Networker] Questions on Oracle RMAN channels with NetWorker?



Hi,

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

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

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

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

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

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

Would greatly appreciate any clarification on this.

Bhaskar

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