A 1 TB array that can store 20 TB of de-duped data in it will cost about
$20K.  (A general rule of them is to base your pricing on a 20:1 de-dupe
ratio, then price it at about $1/GB of effective storage.  If you do
that, you'll be close to list price of a lot of products.)  At that
cost, it's very close to the price of a tape library fully populated
with tapes and drives.

As to whether or not it's worth it for a given setup, you should
obviously test it vs the pricing, but it's very uncommon for it to not
make sense financially.  I can think of three setups that are known
issues:

1. If you're using it for disk staging and not storing any retention on
it.  A lot of the de-dupe comes from de-duping full backups against each
other.

2. If you're trying to de-dupe non-dedupe-able things, such as seismic
data, medical imaging data, or any other data types that are
automatically created by a computer (as opposed to database entries and
Word docs.)

3. If your backup product doesn't do full backups of filesystem data,
you will not get as much as other people.

Everything is also negotiable.  If you've tested and you're not getting
the advertised de-dupe ratio, use that in the negotiation stage.  If
they generally advertise 20:1 and you're only getting 10:1, it would
seem reasonable to assume a 50% discount.

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

-----Original Message-----
From: Ed Wilts [mailto:ewilts AT ewilts DOT org] 
Sent: Saturday, September 22, 2007 9:47 AM
To: Curtis Preston; 'Justin Piszcz'; 'Jeff Lightner'
Cc: veritas-bu AT mailman.eng.auburn DOT edu
Subject: RE: [Veritas-bu] Tapeless backup environments?

But Curtis, a disk drive by itself isn't very useful either - you'll
need to
a controller or two.

And don't forget to factor in the price of the de-duplication appliances
or
software.  Those suckers are *NOT* cheap.  An appliance to support 1TB
of
compressed data lists out at about $20K.  Unless you get a *lot* of
de-duplication - and not everybody does - that appliance is going to get
killed on price compared to not de-duping it.

It took me only 30 minutes with a de-dupe vendor last week to eliminate
their product from consideration in our environment.

        .../Ed

--
Ed Wilts, RHCE, BCFP, BCSD
Mounds View, MN, USA
mailto:ewilts AT ewilts DOT org


> -----Original Message-----
> From: veritas-bu-bounces AT mailman.eng.auburn DOT edu [mailto:veritas-bu-
> bounces AT mailman.eng.auburn DOT edu] On Behalf Of Curtis Preston
> Sent: Friday, September 21, 2007 12:10 PM
> To: Justin Piszcz; Jeff Lightner
> Cc: veritas-bu AT mailman.eng.auburn DOT edu
> Subject: Re: [Veritas-bu] Tapeless backup environments?
> 
> First, you can't compare the cost of disk and tape directly like that.
> You have to include the drives and robots.  A drive by itself is
> useful;
> a tape by itself is not.
> 
> Setting that aside, if I put that disk in a system that's doing 20:1
> de-duplication, my cost is now 1.65c/GB vs your 3-9c/GB.
> 
> ---
> W. Curtis Preston
> Backup Blog @ www.backupcentral.com
> VP Data Protection, GlassHouse Technologies
> 
> -----Original Message-----
> From: veritas-bu-bounces AT mailman.eng.auburn DOT edu
> [mailto:veritas-bu-bounces AT mailman.eng.auburn DOT edu] On Behalf Of Justin
> Piszcz
> Sent: Friday, September 21, 2007 7:36 AM
> To: Jeff Lightner
> Cc: veritas-bu AT mailman.eng.auburn DOT edu
> Subject: Re: [Veritas-bu] Tapeless backup environments?
> 
> 
> I believe disks are 33c/gigabyte and tapes are 3-9cents/gigabyte or
> even
> 
> cheaper, I do not remember the exact figures, but someone I know has
> done
> a cost analysis and tapes were by far cheaper.  Also something that
> nobody
> calculates is the cost of power to keep disks spinning.
> 
> Justin.
> 
> On Fri, 21 Sep 2007, Jeff Lightner wrote:
> 
> > Disk is not cheaper?  You've done a cost analysis?
> >
> > Not saying you're wrong and I haven't done an analysis but I'd be
> > surprised if disks didn't actually work out to be cheaper over time:
> >
> > 1) Tapes age/break - We buy on average several hundred tapes a year
-
> > support on a disk array for failing disks may or may not be more
> > expensive.
> >
> > 2) Transport/storage - We have to pay for offsite storage and
> transfer
> -
> > it seems just putting an array in offsite facility would eliminate
> the
> > need for transportation (in trucks) cost.  Of course there would be
> cost
> > in the data transfer disk to disk but since everyone seems to have
> > connectivity over the internet it might be possible to do this using
> a
> > B2B link rather than via dedicated circuits.
> >
> > 3) Labor cost in dealing with mechanical failures of robots.   This
> one
> > is hidden in salary but every time I have to work on a robot it
means
> I
> > can't be working on something else.   While disk drives fail it
> doesn't
> > seem to happen nearly as often as having to fish a tape out of a
> drive
> > or the tape drive itself having failed.
> >
> >
> > -----Original Message-----
> > From: Justin Piszcz [mailto:jpiszcz AT lucidpixels DOT com]
> > Sent: Friday, September 21, 2007 10:08 AM
> > To: Jeff Lightner
> > Cc: veritas-bu AT mailman.eng.auburn DOT edu
> > Subject: Re: [Veritas-bu] Tapeless backup environments?
> >
> >
> >
> > On Fri, 21 Sep 2007, Jeff Lightner wrote:
> >
> >> Yesterday our director said that he doesn't intend to ever upgrade
> >> existing STK L700 because eventually we'll go tapeless as that is
> what
> >> the industry is doing.   The idea being we'd have our disk backup
> >> devices here (e.g. Data Domain) and transfer to offsite storage to
> >> another disk device so as to eliminate the need for ever
> transporting
> >> tapes.
> >>
> >> It made me wonder if anyone was actually doing the above already or
> > was
> >> planning to do so?
> >>
> >
> > That seems to be the way people are 'thinking' but the bottom line
is
> > disk
> > still is not cheaper than LTO-3 tape and there are a lot of
> advantages
> > to
> > tape; however, convicing management of this is an uphill battle.
> >
> > Justin.


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