Long Term Data Storage

I’ve had a few people ask me just recently what method I would recommend when planning a long term backup strategy.  One elderly gentleman in particular was creating a family time capsule that he wanted his children and grandchildren to be able to view many decades from now.

The question isn’t as easy as you may think.  You may imagine that the data could be burnt to CD,locked in a cupboard and that it would last forever however unfortunately this isn’t the case.  There are literally hundreds of suitably stored but physically decayed CD’s from my teenage years which I could use as testament to that.

Therefore I’ve made a list of common formats one would usually consider for archiving a large amount of data so you can pick the most suitable one for your needs:

Hard Disk – When used on a regular basis a hard disk will typically last for around 5 years before it starts to decay and if it is being used as an infrequently accessed backup drive then we can assume that this can be at least doubled.   Unfortunately degradation of the discs metallic surface,along with the inevitable seizing of parts would still occur over an extended period of disuse.

Optical – Standard optical media includes CD, DVD and BluRay.  If choosing this media type ensure that you go for the highest grade money can buy you;a premium brand such as Taiyo Yuden may well last a decade but a more budget brand such as Memorex may only last half that time before the aluminium starts separating from the plastic.

Flash Media – Clearly you would expect that since Flash Media has no moving parts it would be ideal for a long term backup strategy.  To an extent you would be right but the published data retention of a unused flash drive is only around 10 years and unfortunately once the device has reached the end of its life it is likely that it will go out in style,taking with it all of the information stored within.

Paper – Rather obvious this one –if left in a dark,dry place then paper will last for many decades;we recently recovered a number of newspapers from 1964 from below the flooring of a building we’re doing up and aside from being a little yellowed they’re in perfect condition.  Primary problems do of course include having to find a safe place to store them along with the physical limitations relating to the amount and type of information that can be stored on sheets of paper.

Tape –This may come as a surprise,but Tape backup actually holds one of the best data retention rates hence its continued use in banking and government sectors.  Typically a manufacturer will warranty a tape for 30 years with an expected life expectancy beyond that.   Although the tapes themselves are affordable and the capacities typically high (between 72GB and 1TB compressed),the actual drives themselves are relatively expensive,starting at £250 for a basic model. 

Unfortunately that’s it for this week;we’ll conclude next Friday by covering the remaining options,including a storage media that’s provided with a remarkable 100 year warranty.

Last week I spoke about a gentleman I met who was creating a family time capsule and had come to me to ask the most effective way of achieving data that he wished to be available past beyond his lifetime.

The question is an interesting one as when you look in to the technology available you realise that many forms of media are simply incapable of storing important data for more than a couple of years.   By way of example,a couple who videotape the early years of their child on to a DVD disc may be disappointed when ten years down the line the data has been destroyed by way of natural degradation of the media.

The last article already discussed the pros and cons of Hard Drives,Optical Media,Flash Drives,conventional Paper and Tape drives and so this week conclude with the remaining options I would consider:

Solid State Drive – An SSD uses solid-state memory (similar to that used in a flash drive) to store data and is most commonly used as a direct alternative to a hard drive,especially in notebooks where their small weight and size along with fast access times make them ideal.  Unfortunately,they suffer the same major problems as flash drives in that JEDEC,the leading developer of standards for solid-state storage specify that data retention of an idle drive should only be considered to be around 10 years.

The Internet – The Internet is theoretically the most robust way of backing up data;an online server is typically backed up daily,monitored 24/7 and in the event of a problem with the hard drive housing your data,a redundant mirrored backup drive would immediately take over.  If looking to store data that will be used in your lifetime this would be a suitable option however if the intention is to preserve data for future generations (such as the time capsule idea that inspired this article) then this method could be ill-advised.  For example,if you backup data using a free online storage account then there’s nothing to say that the company won’t either go out of business or begin charging for the service in the future – these are both circumstances that would lead to the deletion of your data.

Magneto Optical – Although it is certainly a niche product,Magneto Optical might be your best solution if long term data storage is your goal.  Originally introduced in the 1980’s,MO drives are slow and currently have a maximum capacity of just 9.1GB however with their slow speed comes a ruggedness that allows manufacturers to provide their discs with a 100 year data retention claim,often with a warranty to match.  High end drives are expensive but you could enter the market with a 1.3GB drive for around £100.

Of course,when devising a long term archival strategy we assume that hardware will be available at the time that it needs to be played back.  This is a serious consideration when we’re talking about storing the data for best part of a century but in our own lifetime it won’t necessarily be a problem –the first video camera my family owned used the 8mm Video8 cassette tapes and although 20 years down the line I don’t own a compatible reader,I could obtain one if necessary.

Along with choosing the most suitable format,ensure that you keep copies on several different media types and in several different locations,thereby increasing your chances that one media type in one location will survive the test of time.  If possible,check on the media every couple of years and transfer it to  newer and more suitable media types.