Networker

Re: [Networker] 2 Part Question

2007-05-15 12:18:52
Subject: Re: [Networker] 2 Part Question
From: Stuart Whitby <swhitby AT DATAPROTECTORS.CO DOT UK>
To: NETWORKER AT LISTSERV.TEMPLE DOT EDU
Date: Tue, 15 May 2007 17:17:29 +0100
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.
 
For your second question, it depends exactly what you're hoping to achieve by 
using backup to disk, what your tape drive performance and availability is, and 
what policies you're using to temporarily retain that data on disk.  There are 
a few scenarios:
 

*       
        You intend to run full backups to disk over the weekend and clone that 
data to tape slowly throughout the week.  Daily incremental data will go direct 
to tape.  Savesets will remain on disk until (for example) the Friday evening 
before a Saturday morning backup.  Space required: 1.2TB minimum.
*       
        You intend to run all of your backups to disk and keep these available 
for immediate file recovery until the next full backup runs.  Data is cloned to 
tape slowly through the week, deleted from disk just before that full backup.  
Space required: 1.2TB + 1 week's worth of nightly incrementals.
*       
        You intend to back up to disk, stage immediately to tape for recovery 
performance reasons and remove backups from disk.  Space required: 1.2TB 
(auto-emptied regularly).
*       
        .............

If you can let us know exactly what you intend to achieve by using this, we can 
better advise as regards how much space you'd need etc.  

HTH,

Stuart.


________________________________

From: EMC NetWorker discussion on behalf of Patricia Neal
Sent: Tue 15/05/2007 14:25
To: NETWORKER AT LISTSERV.TEMPLE DOT EDU
Subject: [Networker] 2 Part Question



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?

Also, when setting up advanced file systems, what is the rule as far as how 
much free space I need in order to be successful. An example would be, on the 
weekends I might create my full backups from 4 separate groups containing 
approx. 300GB's of data each. How much disk space will I need in order to 
perform this task and also move the data to tape eventually. ( like within the 
week)

Patricia Neal
Production Support Specialist
C.S.E.A.

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