Veritas-bu

Re: [Veritas-bu] Tapeless backup environments?

2007-09-24 13:02:27
Subject: Re: [Veritas-bu] Tapeless backup environments?
From: "Jeff Lightner" <jlightner AT water DOT com>
To: <dave.markham AT fjserv DOT net>
Date: Mon, 24 Sep 2007 11:51:05 -0400
Data Domain makes a hardware storage device (disks) which does
deduplication.  Rather than backing up block for block all the time it
does it only for the first backup.  For subsequent backups rather than
doing an incremental backup at file level it backups up incrementally at
block level meaning only the blocks that changed in the source are
stored on the target.

The benefit to this is good for things like databases on filesystems
where the datafile gets updated for any write to the datafile.   A
standard file incremental would backup the entire datafile but a
deduplication incremental would only backup the blocks modified within
the datafile.   One can get what appears to be a very high level of
compression to the deduplication storage.   I've seen numbers like 20:1
and even one person on this list last year said something like 80:1
though that wouldn't be typical.

Data Domain isn't the only deduplication company out there and we
haven't yet implemented the ones we bought (though we will before the
end of October).   I was contacted off list by another company called
Sepaton but there solution seemed to require one to one correspondence
between original storage and target storage.  I believe there is at
least one other company doing deduplication but I don't recall who
(Falconstore maybe)?


-----Original Message-----
From: Dave Markham [mailto:dave.markham AT fjserv DOT net] 
Sent: Monday, September 24, 2007 11:35 AM
To: Jeff Lightner
Cc: veritas-bu AT mailman.eng.auburn DOT edu
Subject: Re: [Veritas-bu] Tapeless backup environments?

Guys i've just read this thread and can say im very interested in it.
The first thing is i learned a new term called deduplication which i
didn't know existed.

Question : I gather Deduplication is using other software. DataDomain i
think i saw mentioned. Where does this fit in with Netbackup and does
the software reside on every client or just a server somewhere?

Ok, so im trying to kit refresh a backup environment for a customer
which has 2 sites. Production and DR about 200 miles apart. There is a
link between the sites but the customer will probably frown on increased
bandwidth charges to transfer backup data across for DisasterRecovery
purposes.

Data is probably only 1 TB for the site with perhaps 70% being required
to be transfered daily to offsite media.

Currently i use tape and i was just speccing a new tape system as i
thought by using disk based backups, and retentions of weekly/monthly
backups lasting say 6 weeks, im going to need a LOT of disk, plus the
bandwidth transfer costs to DR site

LTO3 tapes are storing 200gb a tape which is pretty good compared to
disk i thought.

I guess in my set up its a trade off between :-

Initial cost of disk array vs initial cost of tape library, drives and
media

Time take to backup ( network will be bottle neck here. Still on 100Meg
lan with just 2 DB servers using GigaBit lan to backup server.

Offsite transfer of tapes daily to offsite location vs Cost of increased
bandwith between sites to transfer backup data.


Im now confused what to propose :)


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