I did a quick calculation based on what I have in the vault today and came
up with some interesting numbers about the direction of data storage rates.

Umatic 500 * 2 * 0.35GB=350GB (1981-1996)
DAT 600 * 2 * 0.65GB=780GB (1988-2000)
CD-R 900 * 0.75GB=675GB (1992-2010)
3324 200 * 12 * 0.75GB=1800GB (1988-2000)
DTRS 800 * 8 * 1GB=6400GB (1997-2006)
Hard Drives 600 * 1500=900000GB (0.9PB) (2001-Present) (This is a
guesstimate. In the beginning there are some 100 and 500GB drives, but we
have been burning though about 100 3tb drives a year for the last 3 years
and it is only getting larger)

At LTO7 prices of $48/TB for redundant copies plus $6000 for a pair of LTO7
drives, is virtually identical to a pair of 12 drive storage servers with
spinning discs at $52/TB 10 drive RAID6 with 2 hot spares.
The bigger difference here is the cost of electricity. A pair of servers
running 24/7/365 is about $900/year. (3741kWH * $0.12=$445/yr each)
So by my calculation, up to around 50 TB it makes sense to have online
spinning storage, beyond that offline tape makes more sense.
All the best,

On Thu, Jan 28, 2016 at 10:54 AM, Richard L. Hess <[log in to unmask]>

> I concur with Corey here--I responded to Tom's new thread at greater
> length, but tape was much more economical than spinning disks a decade ago,
> and both have scaled upwards, moving the crossover point.
> I'm now at the 10 TB level for dual RAID-6 local storage with an
> additional 5 TB of single RAID-6 local storage.
> A funny story about Sony marketing. In the late 1990s they showed a robot
> that could hold 1000 TB of data on tape. They called it the Peta-File. The
> next year, it was changed to Peta-Site. That was a decade and a half ago.
> My contention is that tape does not make sense for data storage until you
> have a complete robotic system which includes tape cassette usage history
> and automatic regeneration of tapes that have been used a number of times.
> While the number of "full file passes" on LTO tape has increased, it is
> still relatively low and it's not useful for storage with many retrievals.
> Anything that requires manual storage module shuffling is doomed to not be
> used as regularly as necessary--personal experience with my off-site backup
> confirms this.
> Here is an example of where I think LTO tape (and I think LTO is now the
> only viable data tape format) becomes useful:
> This is a continuation of what I knew as ADIC storage, they were bought
> out by Quantum in 2006.
> It is now a no brainer (in my opinion) to provide 10-20 TB in a single
> RAID-6 enclosure. Eight 3 TB drives in a RAID-6 configuration provides for
> about 15.8 TB of usable storage. Going to 4 TB drives would increase that
> to about 21 TB. (Rememeber, drives are measured using 1000X multipliers
> while files are measured using 1024X mulipliers. Linux properly calls those
> numbers TiB and GiB (for binary).)
> 6 TB drives are commonly available now in RAID-tuned HDDs and for backup
> use (not server use) the WD Red drives seem to be good. I am using this
> line in 2, 3, and 4 TB (8, 8, 5 of each, respectively). So far, I had to
> replace one 3 TB (which were new at the time) about 8,000 hours was
> an easy warranty replacement.
> My main server states.
> Used: 8.45 TB
> Available: 7.41 TB
> Cheers,
> Richard
> On 1/27/2016 8:57 PM, Corey Bailey wrote:
>> Hi Tom,
>> The answer is relatively simple: Money
>> You and I think about storage in terms of a Terabyte or two. General
>> Motors and corporations of that size have to think in terms of multiple
>> Peta-bytes. LTO becomes the least expensive method. After the data is on
>> the tape, verification and migration is done robotically.
>> Those that are considering LTO need to know that the format (drives,
>> etc.) is only backward compatible for two generations and LTO-7 is on
>> the horizon.
>> Cheers!
>> Corey
>> Corey Bailey Audio Engineering
>> On 1/27/2016 4:36 PM, Tom Fine wrote:
>>> <SNIP>
>>> Could someone explain why a somewhat antiquated magnetic tape-based
>>> storage system is preferable to several copies across several hard
>>> drives? I just can't see any sense in using tape systems anymore for
>>> data security, but I'm not a computer-storage expert, just a guy who
>>> stores a lot of data.
>>> -- Tom Fine
>>> ----- Original Message ----- From: "Hood, Mark" <[log in to unmask]>
>>> To: <[log in to unmask]>
>>> Sent: Wednesday, January 27, 2016 6:41 PM
>>> Subject: Re: [ARSCLIST] LTO vs HDD
>>> Hi Richard,
>>> Thanks as always for sharing your experience and insights on all of these
>>> topics.
>>> Would you be comfortable sharing the make and model of the RAID-6 NAS
>>> units you are using, and any comments about how well they have performed
>>> to your expectations?
>>> Thanks,
>>> Mark
>>> Mark Hood
>>> Associate Professor of Music
>>> Department of Recording Arts
>>> IU Jacobs School of Music
>>> On 1/27/16, 3:36 PM, "Association for Recorded Sound Discussion List on
>>> behalf of Richard L. Hess" <[log in to unmask] on behalf of
>>> [log in to unmask]> wrote:
>>> Hi, All,
>>>> I saw this thread and was going to ignore it, but decided not to once I
>>>> found out that RDX was HDD-in-an-otterbox merci, Henri, and thanks for
>>>> the image, Lou. Otters are wonderful--see "Ring of Bright Water" (The
>>>> book) and Point Lobos State Park.
>>>> LTO was around while I was still doing broadcast consulting and, at the
>>>> time (late 1990s, early 2000s).
>>>> I struggled long and hard about how to store things and realized if I
>>>> were going to become involved with LTO, I would need two drives (how
>>>> else can you be even remotely certain that your tapes are readable once
>>>> your single drive dies--I certainly saw that in the early days of PC
>>>> tape backup. At that point, the cost becomes excessive.
>>>> My philosophy now is: Any data I want to keep does not live solely on a
>>>> PC.
>>>> I have two in-house RAID-6 NAS units,  one backing up the other; an ammo
>>>> case of 2.5-inch HDDs off-site (2 TB 2.5-inch USB 3.0 drives are pretty
>>>> economical these days and are USB-powered).
>>>> One son has been migrated to the cloud where Dropbox backs up and
>>>> mirrors his two on-site laptops. Here, I harvest all new files (but not
>>>> updates to prevent pollution of existing files) and store them on my
>>>> RAID-6 NAS units to protect against a Dropbox failure or hacking. The
>>>> other son will do it soon,  but the first one is potentially going far
>>>> away to school next fall for his Masters (Wichita and Edmonton are on
>>>> the list) so I wanted to get some closer-in history with the system.
>>>> RAID-6 allows the failure of any two disks without losing data and the
>>>> data does not have to be chopped up into 1 or 2 TB chunks as it does
>>>> with HDDs.
>>>> I do not keep CF/SD cards, I copy and verify the copy and then recycle
>>>> them.
>>>> Cheers,
>>>> Richard
>>>> --
>>>> Richard L. Hess                   email: [log in to unmask]
>>>> Aurora, Ontario, Canada                             647 479 2800
>>>> Quality tape transfers -- even from hard-to-play tapes.
>> --
> Richard L. Hess                   email: [log in to unmask]
> Aurora, Ontario, Canada                             647 479 2800
> Quality tape transfers -- even from hard-to-play tapes.