Hi Joshua
Just to add to what Frank has said - it's worse than that, As far as I know, 
the DataDomain uses 'Variable Length Segment' to de-duplicate, so not even 
block level.

We've hit space issues on ours - thought we were going to be able to have a 
much longer retention period than we actually could, so I ended up writing a 
script to remove everything over 'n' days old just to get some space back.
In reality, this did help, though not as much as I'd have liked for the very 
reason Frank mentions.

We do use staging and again, I see small returns on space.
A typical full backup of all our systems is probably something like 20TB.  When 
Networker expires those that have reached their retention period, I'm lucky to 
see the Data Domain recover 300GB on its weekly cleaning cycle.

I love the Data Domain, but sizing them seems to be a black art, and we 
certainly got it wrong big time in our organisation.  We'll probably be moving 
away from it in the next 1-2 years which is a shame, but we can't expand the 
systems we're running (DD690) anymore so it would be new head unit and the cost 
is just bonkers, as is the maintenance.  There's talk of going back to tape!

Cheers... Allan.



-----Original Message-----
From: EMC NetWorker discussion [mailto:NETWORKER AT LISTSERV.TEMPLE DOT EDU] On 
Behalf Of Frank Swasey
Sent: 07 September 2011 12:31
To: NETWORKER AT LISTSERV.TEMPLE DOT EDU
Subject: Re: [Networker] Manually staging savesets from adv_file volume to tape

On Tue, 6 Sep 2011 at 3:05pm, Vooris, Josh wrote:

> I am writing all of my savesets to adv_file volumes on a Data Domain unit.  I 
> am starting to run into some space issues, and I would like to manually stage 
> off some of my oldest Monthly backups to tape in order to free up some space 
> on the Data Domain box.  It is my understanding that I could use the nsrstage 
> command with an mminfo query to provide the list of SSID's, but I am not sure 
> of the syntax for these commands.  Could someone provide me with some advice? 
>  My NW server is running Windows 2003 with NW 7.6.1.  Thanks in advance.

Joshua,

While you can use nsrstage to free up space (and I've done it in the 
past) it is not a good thing to do with a datadomain device that is (in 
theory) storing one copy of each block of data.  When you stage 300TB to 
tape, you may actually not save a single byte of space on the datadomain 
(because you didn't get rid of every copy of any block of data).

With that caveat, here's an answer to your question:

I assume you have the nsrstage manual page, you just need to get the 
ssid and cloneid you care about from mminfo and then use nsrstage with 
the -S ssid/cloneid option to move the data to the tape pool you desire 
(-b option).

-- 
Frank Swasey                    | http://www.uvm.edu/~fcs
Sr Systems Administrator        | Always remember: You are UNIQUE,
University of Vermont           |    just like everyone else.
   "I am not young enough to know everything." - Oscar Wilde (1854-1900)

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