Tape storage: past, present and future

null

The story of tape goes back to the very first computers, the original mainframes from the 50s and 60s. These early computers made use of magnetic tape drives with a capacity of 1-2 MB and transferred data at less than 10 KB per second. Current LTO tape drives can store up to 6 TB (that’s approximately 1,500 movies or 1,200,000 songs) at speeds of 300 MB per second.

Amid a flurry of new trends, technologies and buzzwords in the storage industry, this article revisits tape and its current role. What is tape and how does it work? Where does it fit in to today’s digital universe? And most importantly, what is the magic formula that continues to put this storage medium at the forefront when it comes to preserving the largest volumes of the world’s most important data?

What is tape?

Magnetic tape refers to the storage medium where data bits are recorded on a substrate of Mylar plastic. This tape is wound on a reel with heads that perform physical reads and writes, and motors to advance or rewind, all enclosed in a plastic or metal case. The main difference between the cassette tapes of the 80s and 90s and modern enterprise-grade backup tape is that the latter makes use of electronic circuits, stronger materials and grip points for robotic arms. Modern tape libraries rely on high-speed robots that retrieve, load, organise and maintain the tape media.

Linear Tape-Open (LTO) is the most common format and industry standard. Each new generation offers increased capacity. The seventh generation of LTO (LTO-7) was introduced in 2015, providing 6 TB native (uncompressed) capacity per cartridge. It is expected that an eighth generation (LTO-8) will ship in the last quarter of 2017 and offer a capacity point of 12 TB. As well as LTO, a few vendors offer enterprise tape, designed for large customers with high duty cycle requirements.

Over the last few decades, tape has met the long-term backup and archive requirements of numerous organisations, and it is still one of the most cost-effective ways to store large volumes of cold or inactive data. While it is does not offer the highest levels of performance or the lowest latency, tape storage boasts four vital benefits which demonstrate how it has stood the test of time. The innovation around tape and its ability to integrate with modern systems has kept this storage medium very much alive. 

First of these advantages is tape’s flexibility: tape can be implemented in a block, file or object storage environment. This means that it can be integrated into any storage solution or IT environment. Secondly, tape is extremely dense and therefore requires less floor space and power, offering cost savings and a lower environmental impact. Additionally, with a very high level of data integrity over a long period of time, tape enables organisations to meet security and data retention period requirements. And finally, it offers the most competitive cost per capacity compared to other storage media. Despite newer technologies such as flash, tape storage continues to be developed and refined and remains relevant and valuable to the modern datacentre. It is still the medium of choice for preserving important data safely and cheaply over a long period of time.

Tape is dead?

An online search for “tape is dead” now reveals more articles that contradict this widespread myth than support it. Many organisations replaced tape with disk as a backup medium however this decline appears to simply be part of technology’s natural life cycle. Disk storage itself is currently losing out in favour of flash, both at the high-end, high speed market and the low-end consumer market, for example in laptops.

The role of tape has evolved as its use for backup is in decline while its use for archiving and cold storage is on the rise. Current research indicates that small tape systems used by small to medium enterprises for archive and disaster recovery purposes are being replaced by cloud-based storage solutions. Yet, at the same time, large cloud providers are adopting tape, either as the medium of choice to back up their data farms or to provide an archive tier of storage to their customers. 

As more and more of society’s core information, collective knowledge and data is now digital, its survival in the face of diverse threats – from a defect in firmware to a tropical storm or attack – is of the upmost importance. The book Society’s Genome by Nathan Thompson explores this vulnerability and proposes how a successful data storage strategy mimics genetic diversity in nature by having multiple copies of this collective digital knowledge – or genome – in various geographical locations and on diverse media. Tape, offering economic advantages and being the most reliable media for long-term data preservation is a vital part of this strategy.

Tape has been adopted by a wide range of industries where the loss of data could have a catastrophic impact, both for individuals and for society as a whole. For example, tape is the medium of choice for the high-performance computing industry which requires fast and easy access to substantial volumes of critical data. Its reliability, scalability and affordability make tape a highly attractive choice for academic and supercomputing institutions that are home to some of the fastest computers in the world.

Furthermore, medical and healthcare organisations are required to store vast quantities of sensitive data such as historic patient records, corporate data, and x-rays and scans that increase in resolution as technology advances. Tape provides this additional storage space without incurring large costs. Companies within the oil and gas industry as well as renewable energy providers and other large industrial enterprises produce and record large volumes of data that must be accessible to multiple users at a moment’s notice. This includes reservoir metrics, machinery performance, and oil flow rates and pressures. A reliable, scalable and accessible backup and archive system is a priority for these companies.

In addition, Media and Entertainment (M&E) companies such as production and streaming organisations require the backup, archive and accessibility of large volumes of data and video. Production companies add significant amounts of footage to their datacentres each day, often shot in data-intensive raw camera format which must be readily accessible throughout the production process as well as at a future date. For example, video footage of Princess Diana suddenly became extremely valuable after her death in 1997. For the M&E industry as well as research facilities, universities, museums and others, tape is the medium of choice for reliable, long term and affordable data preservation and storage.

Future roadmap

Tape is certainly not dead; rather, it is establishing its place in the modern datacentre. Offering reliability, economic savings and flexibility as well as environmental benefits, it plays a vital role in the storage environments for many organisations. It is well suited for archive, cold storage and backup use cases, and it can be paired with faster mediums for primary storage.

Its future roadmap is strong and the technology continues to improve and develop. LTO has an openly accessible roadmap showing how each succeeding generation offers performance and capacity improvements while guaranteeing backward-read compatibility with previously written tapes.

In terms of capacity developments, tape has the greatest potential compared to all other storage media. This is because it has considerably more surface area – 3,000 feet of tape compared to seven 3.5-inch disk platters or one optical DVD – on which to deposit data than any other medium. Researchers recently demonstrated that this greater surface area has the potential to enable capacities of upwards of 220 TB of storage per cartridge. This possibility of capacity improvement also promises significant reductions in the cost per GB of tape storage, another key factor determining its longevity.

Tunnelling magnetoresistance (TMR) technology is being implemented and will further enhance tape’s potential capacity point. TMR is a method that varies the direction of magnetic current in order to alter electrical charges and it will replace the previous giant magnetoresistance (GMR) drive heads currently found in tape drives. The technology will further maximise surface area by reducing the area of media to which data bits are written. Spinning disk hard drives transitioned from GMR to TMR in 2004 and enabled capacity to double. Tape is now undergoing a similar shift and it is expected that this will allow the capacity to double four more times. With TMR, the eighth generation of LTO (LTO-8) will offer a 12 GB capacity point, twice the capacity of LTO-7.

In addition to TMR, the implementation of highly magnetic material barium ferrite, with a high packing density, and the use of shelves or containers to store tape cartridges instead of traditional tape slots, offer further capacity improvements.

Furthermore, performance is enhanced with each generation. Robot arms have undergone various updates and refinements to increase the speed with which specific tapes within a library can be accessed. Cleaning options to remove debris from media enable the tape systems to run at peak performance. Improvements in data compression techniques such as Streaming Lossless Data Compression (SLDC) as well as speed-matching and data buffers have been developed in order to avoid damage to the tape reel and ensure performance.

Due to the year-on-year revenue declines, the industry suffers from a widespread belief that the demand for tape is inflexible and this has affected how aggressive or competitive product roadmaps and associated media pricing can be. Moving forward, tape vendors are widening the price difference between tape and magnetic disk by continuing to increase capacity and reduce media costs.

A recent whitepaper predicts that “A probable long-term scenario is one in which flash technology and tape will coexist, and become the prevailing storage technologies for online and archive needs, respectively.”

Cloud providers are increasingly selected by small and medium enterprises for archive and disaster recovery strategies instead of small tape systems. These cloud providers, who have a strong incentive to lower the TB/$ ratio, are in turn installing large tape systems. It is likely that cloud providers will mostly adopt LTO which will lead to a greater proportion of LTO compared to enterprise tape technology in the market. The same whitepaper forecasts that “Enterprise tape, with two suppliers, appears to be an over-served market and Spectra Logic predicts that, at some point, the market will converge to one.”

To sum up, while it dates back to the initial datacentres, tape is neither old nor obsolete: the technology sees continued innovation and development and many organisations have been reaping its benefits for a long time. Despite suffering from some outdated perceptions and sometimes being overlooked in favour of newer fast and flamboyant technologies, when it comes to long-term cost effective data preservation, tape storage far surpasses the other media, meeting many current IT priorities – reliability, savings, scalability, flexibility and security – making it a vital part of the future datacentre and modern storage outlook.

Brian Grainger, Chief Sales Officer, Spectra Logic Corporation
Image source: Shutterstock/Scanrail1