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This question was inspired by How to store and preserve lots of data?
There have been another similar questions, but none with this type of criteria.

This is two questions in one.

  1. How do you store financial/critical records that should survive anything but a fire and should be available for decades?
  2. Lets say I want to store family photos/videos and want people do be able to find them in storage 100 years from now and still be able to use them. How would this be done?

Criteria

  1. Long term means 30+ years guaranteed. 100+ years average. [If this is not practical, use the closet solution]
  2. High volume means a couple terabytes.
  3. Answers can be 'no-compromise/industrial' solutions or practical solutions for the home office/small business user.
  4. Media will not be active during the timespan. (ie, if you suggest hard drives, they will not be spinning).
  5. Further, there is no expectation of needing to read these archives. They are there for emergency or "for future generations" purposes.
  6. Should not require maintenance (if at all possible).


My thoughts:

  1. CD-R/DVD-R's have proven to me, even in the short term, to be a terrible medium for backups. They seem to be very fragile and seem to loose their data a very short time even when in pristine condition.
  2. I can't help but think that storing data on a couple of 1TB hdd's and then expecting them to spin up correctly a decade or two later to be a terrible idea. Am I wrong?
  3. Industrial tape drives seem like a viable option?
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I'm no expert, but I'd say tape. This question might be better on Server Fault, but I honestly don't think it fits perfectly on either, so I'll decline to vote. It is a good question and should live somewhere. –  Shinrai Jan 4 '12 at 17:57
    
I agree @Shinrai. I am welcome to moving this somewhere else if someone can comment on where it should live. –  user606723 Jan 4 '12 at 18:01

11 Answers 11

up vote 13 down vote accepted

Paper

Other than archival ink on archival paper in sealed storage, no current medium is proven to last an average 100 years without any sort of maintenance.

Archival Paper

Older papers were made from materials such as linen and hemp, and so are naturally alkaline. or acid free, therefore lasting hundreds of years. 20th century paper and most modern paper is usually made from wood pulp, which is often acidic and does not keep for long periods.

Archival Inks

These permanent, non-fading inks are resistant to light, heat and water, and contain no impurities that can affect the permanence of paper or photographic materials. Black Actinic Inks are chemically stable and feature an inorganic pigment that has no tendency to absorb impurities like other ink pigments can.

Redundant storage

Torvalds once said

Only wimps use tape backup: real men just upload their important stuff on ftp, and let the rest of the world mirror it

Which suggests you should not rely on a single copy on a single medium.

Not magnetic media?

http://www.zdnet.com/blog/perlow/the-bell-tolls-for-your-magnetic-media/9364?tag=content;siu-container

  • Typical example of irretrievable degradation of magnetic media.
  • Issues of hardware and software (and data formats)

Not specialized systems

In 2002, there were great fears that the discs would become unreadable as computers capable of reading the format had become rare and drives capable of accessing the discs even rarer. Aside from the difficulty of emulating the original code, a major issue was that the still images had been stored on the laserdisc as single-frame analogue video,

http://en.wikipedia.org/wiki/BBC_Domesday_Project#Preservation

Long Term Personal storage

http://www.zdnet.com/blog/storage/long-term-personal-data-storage/376

  • both the media AND the format can become unreadable.
  • print on acid-free paper with pigment inks and store in a cool, dry and dark place.
  • The first problem is picking data formats for maximum longevity.
  • Avoid using proprietary formats
  • USCSF is transferring all their original tapes - many in now-obsolete formats like BetaSP and VHS - to the 75Mbit motionJPEG2000 format
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1) Can you provide details about this? Will normal hard copies not last that long? (Photos from 100 years ago seems to be fine, AFAIK). 2) If no current data medium will last this long, I suggest that we use the closet solution possible. It's depressing that decades from now we won't be able to look through old boxes and expect to be able to look at any of our old, forgotten photos, etc. –  user606723 Jan 4 '12 at 18:05
    
@user606723: see updated answer –  RedGrittyBrick Jan 4 '12 at 19:11
    
I've figured that laser printing on acid-free paper would be a good way to store data (a few megabytes per page) that has a high probability of being readable in 100-200 years. The software to read it would be relatively simple, and one presumes that scanners will always be available, so the format (so long as not too convoluted) would never really "go away" beyond the ability of a competent amateur to recover. –  Daniel R Hicks Jan 29 '12 at 16:10

For that kind of time spans, anything that already is on paper (or can be easily printed without losing information) would be best to store in that form. Just be mindful of the paper and toner you use for the hardcopy.

As for others, I don't know of a currently used digital medium that would last for those spans of time. If you spend time (and thus money) to refresh your collection, then a magnetic tape might be a viable option - but even then you'd need some redundancy, as you might just find out that a single tape has gone bad (or it might be that the tape drive just happens to mangle the tape on reading it).

And even when you can get the actual media to stand the test of time, you'd still be faced with the issue whether any program could read the media at 30 years from now, let alone 100 years from now.

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Magnetic tape is subject to a number of failure modes, from "print through" to demagnetization over time to the oxide simply falling off the tape. –  Daniel R Hicks Jan 29 '12 at 16:12

There is no easy solution. The archive maintenance is a process, not one-time job. All three currently-available archival media types have their own pluses and minuses, however these arguments apply to all media types:

  1. Nobody stored DVDs or hard disks for 30 or 100 years, for obvious reasons. So there is no track record and nobody knows how the media will age. Artificial aging tests do not prove much, and you rely on vendor's testing, (not impartial).

  2. You must store the media in the controlled environment for best results (constant temperature/humidity, low light, etc.). Otherwise media life is shortened significantly.

  3. You must maintain the hardware and software that reads the media (e.g. SATA interfaces might not be readily available in 30 years from now).

So, in my opinion, the only viable solution for home users or small businesses is this:

  1. Maintain multiple copies of all data on diverse media types (both hard disks and DVDs)
  2. Maintain multiple copies of all data in multiple locations (at home and in your banks's safety deposit box).
  3. Copy all data to new media every so often (e.g. copy to a new hard disk and new DVD disks every 2 years. As the data density grows, you will probably need fewer disks, too.
  4. Maintain paper copies for all critical data, if possible (e.g. print those yearly general ledgers for your business, print most precious family photos, etc.)
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1  
I wonder if there is RAID for DVDs.... ie.. if you store DVDs for two years, you might be seansibly sure that 80% of them would be error free, so you might have two parity disks. Hmmmm. usenet uses parity files I think. Might be worth using something like that for DVD/CD/BD archival. –  user606723 Jan 4 '12 at 19:00
1  
@user606723: This is a very good idea! I suggest using something like multi-volume RAR archive (if the original files are really big) with PAR2 parity files... –  haimg Jan 4 '12 at 19:29
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Interface compatibility would be a major concern; it's been about 30 years since the IBM XT was introduced, yet how many computers today can in any way interface with a pre-ATA hard disk? How many computers built today can even interface with a PATA hard disk without additional hardware (controller card or USB adapter)? –  Michael Kjörling Jan 30 '12 at 9:48

Up to 5TB (or more?) you can securely store up to 30 years on a magnetic tape aka tape drive. This time is proven. Blue-ray recordables shall safely store your stuff up to 30 years also, but it's capacity is around 100GB.

If you have more money, you'd store it on black/white 35mm film. It's assumed that data can be restored (depending on density) for the next 700 years. (German link to wikipedia)

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For the record, writing to 20-50 blu-ray disks is not out of the question. –  user606723 Jan 4 '12 at 18:14
    
I've never heard of data archival on 35mm, although the principle is obvious I suppose. What's the density like? –  Shinrai Jan 4 '12 at 18:41
    
@Shinrai: I dunno the density of film, sorry –  tuergeist Jan 5 '12 at 12:18
    
You can probably figure a density somewhere between 1 and 10 megabits per frame. –  Daniel R Hicks Jan 29 '12 at 16:05
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Nikon's LS-9000 ED scans film at 4000 dpi, giving you 21.4 Mp/frame at 35 mm (24 x 36 mm). If you can use 1/10th of that for actual data storage (allowing for film imperfections, focusing and resolution limitations in the optics at both ends, etc) that's 2 Mb/frame or something like 10 MB for a 36-exposure roll of film and pure black/white. If the scanner's 4000 dpi is the limiting factor, that's 100 MB for a 36-exp roll. Of course, you'd still have to in some other way preserve information on how to read the data, because to the naked eye the frames would likely appear fairly uniformly gray. –  Michael Kjörling Jan 30 '12 at 9:57

I'd go microfilm. I don't know if it is still manufactured, but I'd be surprised if it wasn't. Silver-based negatives last hundreds of years if stored correctly. Of course that is a huge investment, and will take up a whole room for photography and viewing, and that is not counting storage. So that's only if you really MEAN 100 years+ with no maintenance.

If not - and chances are you aren't unless you want to make a time capsule -, just use HDD backups, and copy the whole stuff over to new media in every 10-15 years. Really, there is no better insurance against the aging of the medium than copying the whole thing over every 10 years or so. Better than microfilm, better than clay tablets, better than stone obelisks buried in the desert sand.

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It's true that common CD-Rs and DVD-Rs are not reliable enough for archiving important data. But you can get DVDs that are not so quick to decay:

https://www.google.com/search?q=archival+dvd-r

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I've read that 'M-Disc' have created a DVD which needs a special writer yet is readable on generic DVD readers. They claim an estimatible life span of 1000 years, stating it cannot be accurately tested. Long exposure to the sun, scratches, multiple usage etc and the disc is 100% useable. I'd be interested in any feedback from anyone who's encountered this system.

Here's an excerpt from Dell who maybe installing the M-Disc drive in their new laptops/PC's

M-DISC Ready drives laser-etch data into an inorganic rock-like material to prevent data loss, ensuring your files are safe and can be stored for up to 1000 years, the company claims.

Unlike all other recordable DVDs that use organic dyes to hold data, M Discs won’t fade or degrade over time.

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Instead of reposting with more info, you should have edited your original post. –  Kazark Apr 16 '13 at 19:25
    
Can you cite the quote with a link or something? Also, you can use > to format it as a block quote. –  Kazark Apr 16 '13 at 19:28

I recommend a three inch diameter nickel disk with information microscopically etched onto its surface.

http://rosettaproject.org/blog/02008/aug/20/very-long-term-backup/

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Does it have to be exactly three inches? I have a 75 mm diameter nickel disk handy... –  Michael Kjörling Dec 26 '13 at 21:44

You need to mix different technologies, locations and mediums in order to achieve long life backups:

  • Burn to DVD - Bluray at low speed. Keep them in low light, low temp, low humidity, free of scratch.
  • Keep a copy in a RAID 1, Raid5, Raid6 or Raid10 unit.
  • Keep another copy in an external HDD
  • Keep a copy in the cloud (carbonite, crashplan)
  • Keep a copy on M-Disc technology (Mdiscs and Mdisc burners) are not available at Amazon.com at very good prices. Manufacturer states they can hold data for 1000 years.
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I see three of your five bullet points are really variations of a single theme: magnetic hard drive storage. As for your last point, the issue isn't so much how long the media will retain the data (and at least hard disk manufacturers commonly cite numbers that are far better than reality) but for how long equipment to read the data will be available or knowledge of how to make them will be available. All of your suggested techniques are high-tech. Suppose the Vikings stored data on blu-ray disks; what are the odds we'd have the knowledge how to interpret that data now? –  Michael Kjörling Dec 26 '13 at 21:43

Practical long term data storage using the current technology of the year 2014:

...and this is what I am doing.

Get two of the multi-terabyte drives, for example two drives 3 terabytes each. Call one TB-1 and the other TB-2. Back up everything to TB-1. After a year of backing up to TB-1, re-format TB-2 and copy TB-1 to TB-2. Then for the next year, back up everything to TB-2. After that year, re-format TB-1 and copy TB-2 to TB-1 thereby starting the bi-annual cycle again.

The reformatting restores the magnetic strength of the sector markers. And the copying restores the magnetic strength of the data.

The same principle can be applied to tape backup and CD backup, or most any other backup. But CDs are so inconvenient because they can go bad in less than a year, and you need so many of them to back up everything. So, burning copies of all backup CDs every 5 months is just too much work. So far, I can store my whole life on one multi-terabyte drive.

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CD's go bad in less than a year? Are you saying you don't own any CD more than 1 year old? I have data and audio CD's from more than a year I can assure you, and they work fine! –  Dave May 19 at 14:04
    
I have CDs from 1998 which still work fine. Regardless of us knowing this isn't true, what makes you believe this is the case? Can you source your information? Thanks. –  Matthew Williams May 19 at 14:29

As someone already mentioned there is a new tech called M-Disc. They are very reliable: http://www.zdnet.com/torture-testing-the-1000-year-dvd-7000023203/ We started to use them for securing images of production machines disks. There are already Blu-Rays on the market. Only disadvantage is they are slower than classic B-RDs.

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