Long term data retention

Posted on August 13th, 2014

Businesses today face an ever increasing need to hold onto data for long periods. Not a straight forward additional challenge as technologies do not always favour retaining data for lengthy periods. What storage applications are available on the market place that you should be considering?

Let’s examine them including flash memory, hard disk drives, magnetic tape and optical discs.

Flash Memory, when we are talking long term archiving. This is not an option. Retention is stated at being less than 2 years and costs will be high. This shouldn’t be fully ignored though, it could be a useful tool in transferring cold storage data to your system for instant access.

Hard Disk Drives, are popular in active archival arrays. Users know this product and access to data is relatively quick and costs seem to be acceptable. Again though, these do not last forever. The thermodynamics of these products means they will decay and with that your invaluable data. You should assume here a period of 3 to 5 years to hold your active archive and therefore plans to replace HDD’s over time should be in place. Best practice would be to hold your HDDs in a RAID/NAS solution so that any failures will not result in a loss of data. Capacity in HDDs is growing, currently it is up to 6TB.

This moves us on to what will hold my long term cold data storage?  There are now 3 common digital storage media products available, Magnetic tape, optical disc and RDX.

Magnetic Tape, there are several formats including Enterprise, SDLT and LTO. I will focus on Ultrium LTO tapes, these have roadmap to improve the technology, we could see 100TB+ tapes within 10 years! At this time we are at the LTO 6 generation which holds ‘only’ 6TB of compressed data with backup speeds of 400MB/second. The tapes can be moved and stored with an archival life of over 30 years. Cheap to purchase and no ongoing utility cost. A good candidate for long term data retention, especially with drives now being produced to directly use thunderbolt.

Optical Storage, if your data consumption and retention is low volume then this is a low cost alternative. We all have CDs, DVDs or Blu Ray and so know how these work and with an archival life on professional grade items of 100 years (ensure the Drive technology will exist). Data can be stored and filed knowing that it will be there if ever needed. A test showpiece has recently shown using a Blu Ray disc storage system you could retain up to 1PB of data over 1000’s of discs saving 50% on storage costs and more on energy consumption compared if you were to use a HDD system (Note: a tape solution in my opinion would be better suited for most SMBs). Most businesses won’t be on this level but manufacturers will soon release a 300GB optical disc with a roadmap planned to increase this to 1TB.

RDX, relatively new and unknown. This can be seen as a hybrid of all the other storage devices, it’s random-access like disk drives, it’s portable like tape and it’s compliant like optical. With the portable robust cartridges now at 2TB it should make SMBs interested.

To conclude, Tape and discs provide low cost inactive storage for long term data retention versus HDDs. Depending on your access requirements the best solution, as is generally the case, would be to combine a number of these technologies to gain the right balance and cost to your company.

To discuss your storage requirements please contact us at 02380 736500 or email andy@imagestore.co.uk

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