Networker

Re: [Networker] 2 Part Question

2007-05-15 12:46:43
Subject: Re: [Networker] 2 Part Question
From: Darren Dunham <ddunham AT TAOS DOT COM>
To: NETWORKER AT LISTSERV.TEMPLE DOT EDU
Date: Tue, 15 May 2007 09:37:34 -0700
>> Can someone explain the cloning process to me as to why it would be
>> more efficient to do a restore from a clone pool tape, and why this
>> would be a good idea to use the cloned tapes at a disaster recovery
>> test site to speed up things?

> If you clone on a saveset-by-saveset basis, you demultiplex that
> saveset and create a single chunk of data to read, leading to improved
> restore performance (think of it as defragmenting your tape backups).
> However, there's been recent discussion on this list which suggests
> that there are ways in which the clone backup isn't demultiplexed, in
> which case there would be little benefit apart from redundancy and
> confirmed reliability.

Non-demultiplexed cloning happens if you pass multiple savesets into
nsrclone (instead of running them one at a time), and the savesets are
relatively multiplexed.  Demultiplexing the savesets takes more time
than straight cloning, so the time requirements may not allow you to do
that.

-- 
Darren Dunham                                           ddunham AT taos DOT com
Senior Technical Consultant         TAOS            http://www.taos.com/
Got some Dr Pepper?                           San Francisco, CA bay area
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