Claus,
I think you may be under the impression that I am recommending LTO as
a long-term storage option.
As you know, all platforms (HDD, data storage tape, optical media)
will have to be subjected to a practice of supplemental migration. A
reasonable window of 3-5 years is about the best that you can expect
with the advances in technology. LTO has so far proven that they do
have a roadmap (LTO1/ 2/ 3/ 4/ 5/ 6) and continue to provide
backwards compatibility with previous generations.
> Basically... for any archive that has to work within a budget, any
> physically checking of media can be very expensive if one has to
> invest in
> hardware to accomplish the task... or hire people... I wouldn't
> suggest
> getting the guy from the "corner of the street".
"any physically checking of media" should be done by a professional
IT person, I would agree. But that would appear to hold true for
those who deploy their own RAID array as well. Depending on storage
amounts, a NAS or SAN won't be any cheaper than an LTO drive.
I wouldn't let the "guy from the corner of the street" touch either
system, and there are costs involved either way. LTO-3 WORM media is
currently about $0.25 per GB.
> As an example... we consider ALL physical media as a future
> problem. When we
> archive for LTO we only use half the life expectancy of the drive,
> in the
> hope that future disaster recovery will benefit from us storing the
> original
> drive that generated the tape with the tapes... this is due to head
> alignment etc...
I'm not quite sure that "storing the original drive that generated
the tape" is a useful approach unless you can store repair parts and
a technician that can repair the drive. I would have the data off
the tape well in advance of the manufacturer's claimed life
expectancy. And we have never had to "realign the head" on an LTO
drive.
> Practically, we are located 250 ft underground... and have mirror
> sites
> around the US for physical separation.
You are lucky in that regard. Most archives aren't underground and
DO have to consider geographical separation.
> I have nothing against physical based storage, but my point is that
> anything
> that is based on physical assets will by default deteriorate over
> time...
>
> I hope this clarifies my statements...
I have nothing against mirrored online backup sites! However, your
point "that anything that is based on physical assets will by default
deteriorate" would seem to implicitly include HDD as well.
John Spencer
www.bridgemediasolutions.com
On Jun 3, 2005, at 1:12 AM, Claus Trelby wrote:
> Hi John,
>
> I use mainly LTO for my clients requirements, when it comes to
> tape... with
> great success so far...
>
> Basically... for any archive that has to work within a budget, any
> physically checking of media can be very expensive if one has to
> invest in
> hardware to accomplish the task... or hire people... I wouldn't
> suggest
> getting the guy from the "corner of the street".
>
> As an example... we consider ALL physical media as a future
> problem. When we
> archive for LTO we only use half the life expectancy of the drive,
> in the
> hope that future disaster recovery will benefit from us storing the
> original
> drive that generated the tape with the tapes... this is due to head
> alignment etc...
>
> Practically, we are located 250 ft underground... and have mirror
> sites
> around the US for physical separation.
>
> I have nothing against physical based storage, but my point is that
> anything
> that is based on physical assets will by default deteriorate over
> time...
>
> I hope this clarifies my statements...
>
> Claus.
>
> Claus Trelby
> Managing Engineer/Partner
>
> XEPA Digital
> 1137 Branchton Road, 19-N-3
> Boyers, PA 16020-0137
> www.xepadigital.com
> [log in to unmask]
> P:724-794-3686
> F:724-794-3292
> C:805-490-1730
>
>
>
> -----Original Message-----
> From: Association for Recorded Sound Discussion List
> [mailto:[log in to unmask]]On Behalf Of John Spencer
> Sent: Thursday, June 02, 2005 11:22 PM
> To: [log in to unmask]
> Subject: Re: [ARSCLIST] Testing DVDs
>
>
> Could you please elaborate on your statement:
>
> "Even if you can check a disc type media physically I think it will
> be hard to check something like
> Exabyte or LTO on a regular basis without tearing the media apart..."
>
> Disregarding Exabyte drives and tapes, LTO is the largest selling
> data storage tape drive in the Enterprise IT environment,
> and they seem to be pretty happy with it. Most of the media vendors
> do 1,000,000+ pass testing and are eager
> to share the results (Fuji is very good about sharing their
> information). I agree that RAID is a great option, but
> near-line solutions should be looked at as a potential part of the
> digital archive process.
>
> Geographical separation comes to mind in this instance.
>
> John Spencer
> www.bridgemediasolutions.com
>
>
> On Jun 2, 2005, at 8:59 PM, Claus Trelby wrote:
>
>
>> Hi Peter (all),
>>
>> Without going into physical indicators and complexities for disc
>> media
>> failure, I would just like to add a little suggestion to all of
>> this...
>>
>> We want to preserve the data, right? A minimum of two different
>> types of
>> media for storage plus a checksum file such as MD5 placed in the
>> middle
>> storage area of the media (tape or disc) is our default... we then
>> spot
>> check all media periodically (especially edge content or all
>> content), and
>> any deviation from the checksum results in alerts... Even if you
>> can check a
>> disc type media physically I think it will be hard to check
>> something like
>> Exabyte or LTO on a regular basis without tearing the media apart...
>>
>> Just a suggestion.... I've personally stopped paying attention to
>> accelerated media testing... I find it useless... history always
>> proves it
>> wrong...
>>
>> I believe spinning/exercised RAID disc (HD) storage is the only way
>> to go...
>> still very expensive, but a couple of the companies I am consulting
>> for are
>> getting in the right ball park... less than $4 per GB (22TB
>> minimum)...
>>
>> Claus.
>>
>> Claus Trelby
>> Managing Engineer/Partner
>>
>> XEPA Digital
>> 1137 Branchton Road, 19-N-3
>> Boyers, PA 16020-0137
>> www.xepadigital.com
>> [log in to unmask]
>> P:724-794-3686
>> F:724-794-3292
>> C:805-490-1730
>>
>> -----Original Message-----
>> From: Association for Recorded Sound Discussion List
>> [mailto:[log in to unmask]]On Behalf Of [log in to unmask]
>> Sent: Thursday, June 02, 2005 7:43 PM
>> To: [log in to unmask]
>> Subject: Re: [ARSCLIST] Testing DVDs
>>
>>
>> I will be attending the AES/ISO meeting of the Technical Commission
>> on Tape
>> and Disc preservation this coming week. We have been discussing
>> ways of
>> testing DVD's and it is a subject that is part of next week's
>> agenda. So
>> far, it is unfortunately true that the testing methods developed and
>> recommended are somewhat too cumbersome and time-consuming to be
>> widely
>> practical. If we review any documents that offer reasonable
>> alternatives, I
>> will report such to the list.
>>
>> One of the primary failure mechanisms that needs more testing is
>> delamination. In my opinion, from review of the available data,
>> there is
>> not enough reliable information on the stability and reactive
>> properties of
>> the glue used to bond the layers together. If someone has a good,
>> quick way
>> to test the glue stability, I would be pleased to pass it on to the
>> Commission.
>>
>> One of the problems encountered (again, in my opinion) is that
>> testing for
>> new mediums tends to mimic the tests for previous mediums.
>> Accelerated
>> aging tests for recordable sound media were initially developed to
>> try and
>> test binder hydrolysis. Discs are a very different animal than tape.
>> Polycarbonate disc surfaces do not hydrolyze like polyester binder
>> in tape.
>> On the other hand, reflective mediums in Discs can oxidize while
>> ferric
>> oxide recording pigments in older tape don't. Again, the binder
>> mechanism
>> on tape is integral to the entire recording layer while Discs are
>> actually
>> held together with an added layer of glue.
>>
>> It is quite possible that we need to seriously re-think the testing
>> parameters and methods for Discs. Again, if anyone has some
>> suggestions, I
>> would be glad to pass them along.
>>
>>
>> Peter Brothers
>> President
>> SPECS BROS., LLC
>> (201) 440-6589
>> www.specsbros.com
>>
>> Restoration and Disaster Recovery Service Since 1983
>>
>>
>>
>>> -----Original Message-----
>>> From: Association for Recorded Sound Discussion List
>>> [mailto:[log in to unmask]]On Behalf Of seva
>>> Sent: Thursday, June 02, 2005 9:38 AM
>>> To: [log in to unmask]
>>> Subject: Re: [ARSCLIST] Testing DVDs
>>>
>>>
>>> i think that querying Mitsui itself would yield more information.
>>> they
>>> have a sterling reputation and i'm sure would have no intention to
>>> launch the gold DVDs without serious advanced aging tests of their
>>> own...
>>>
>>>
>>> David Lewiston wrote:
>>>
>>>
>>>
>>>> So there are plenty of brilliant comments, but no practical
>>>>
>>>>
>>> suggestions for
>>>
>>>
>>>> doing a quick and dirty test?
>>>>
>>>> Salutations, David L
>>>>
>>>>
>>>> ----- Original Message -----
>>>> From: "Nigel Champion (ARTS ANT)" <[log in to unmask]>
>>>> To: "David Lewiston" <[log in to unmask]>
>>>> Sent: June 01, 2005 4:35 PM
>>>> Subject: RE: [ARSCLIST] Gold DVD-Rs
>>>>
>>>>
>>>> Then you need to repeatedly insert and remove the DVD-R from its'
>>>> case.
>>>> This is to find how long it takes to separate the two polycarbonate
>>>> layers of the DVD!
>>>>
>>>> Regards
>>>> Nigel
>>>>
>>>>
>>>>
>>>>
>>>>
>>>
>>> --
>>> salutations,
>>> seva
>>>
>>> www.soundcurrent.com
>>> || | | | | | | | |
>>>
>>> Things are not what they seem to be; nor are they otherwise.
>>> -- Lankavatara Sutra
>>>
>>>
>>>
>>>
>>
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