ADSM-L

Re: [ADSM-L] Data Deduplication

2007-08-27 15:12:07
Subject: Re: [ADSM-L] Data Deduplication
From: Charles A Hart <charles_hart AT UHC DOT COM>
To: ADSM-L AT VM.MARIST DOT EDU
Date: Mon, 27 Aug 2007 14:09:58 -0500
Thanks Curtis!

Charles Hart
UHT - Data Protection





Curtis Preston <cpreston AT GLASSHOUSE DOT COM>
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08/27/2007 01:22 PM
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Subject
Re: [ADSM-L] Data Deduplication






I agree that this is what Oracle does.  What I'm not sure is whether or
not this de-dupe issue applies to de-dupe vendors other than Diligent.
I've fired off a few emails and I'll reply when they do.

---
W. Curtis Preston
Backup Blog @ www.backupcentral.com
VP Data Protection, GlassHouse Technologies

-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of
Charles A Hart
Sent: Monday, August 27, 2007 10:53 AM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Re: [ADSM-L] Data Deduplication

According to Dilligent, when RMAN uses Multiplexing, it  intermingles
the
data from each RMAN so the data block will be different every time so
the
blocks are different, similar to Multiplexing with Netbackup...   I'm
not
an RMAN expert, just trusting what the Vendor is stating.

The following link seems to match with what we are being told

http://download.oracle.com/docs/cd/B19306_01/backup.102/b14191/rcmconc10
02.htm
 (Look for the Multiplex Section)

Is there an RMAn expert in the house?  Can some one confirm this info?

Charles Hart
UHT - Data Protection
(763)744-2263
Sharepoint:
http://unitedteams.uhc.com/uht/EnterpriseStorage/DataProtection/default.
aspx




Curtis Preston <cpreston AT GLASSHOUSE DOT COM>
Sent by: "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>
08/27/2007 11:40 AM
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Re: [ADSM-L] Data Deduplication






>        3) Oracle Specific
>                Do not use RMAN's Multiplexing in RMAN will combine 4
>Channels together and the backup data then will be unique every time
thus
>not allowing for                        de-duping)
>                Use the File Seq=1 (Then run multiple channels)

I don't see how this would affect de-duplication if your de-dupe product
knows what it's doing.  Every block coming into the device should be
compared to every other block ever seen by the device.  So combining
multiple files together using Oracle multiplexing shouldn't affect
de-dupe.

Did you test this, or see it in the docs somewhere?  Was this true for
multiple de-dupe vendors, or just the one you chose?



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