Long considered the de facto standard for storing digital information, magnetic tape cassettes and cartridges ruled large computer systems for much of the 1980s and 90s.

However, the arrival of data storage disks led to a significant decline in tape’s popularity, before solid-state storage took the reins in random access non-volatile data storage, and then cloud computing entered the fray – further cementing tape’s perception as dated and inflexible.

One of the reasons that organisations continued to use tape through the rise of disk, solid state and cloud is the fact that it allows an added assurance of offsite storage – a benefit that continues today.

So most data centres continued to deploy tape as well as disk formats, but it is disk that has participated more actively in the exponential data growth of recent years.

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The shiny new alternatives have positioned tape as a dated, costly, inflexible, unreliable technology that few forward-thinking organisations would dream of using as a core part of their data storage and protection infrastructure. With its image bruised and tarnished, it was expected to quietly disappear into IT oblivion.

Only it didn’t. 2014 proved to be quite a resurgent year for tape as investment in new technology created high-performance versions that are far better suited to today’s big data requirements.

First, Sony revealed that it had developed new magnetic tape technology that could allow tape capacity of up to 185 terabytes. Then, Fujitsu announced its own plans to develop a 154-terabyte cartridge that is able to store 85.9 billion bits per square inch on linear magnetic particulate tape.

Durable data

Such developments have waked CIOs up to the realisation that tape does, indeed, still have a place in their storage infrastructure.

‘The biggest advantage of tape over other storage media is the ability to easily swap tapes in and out of a system,’ says Johan Jongsma, CTO of LogicNow’s storage division. ‘That, combined with a lower price per GB stored, means that it could still be an attractive media to store large amounts of data that has to be stored for a long period of time.’

However, many in the industry remain very critical of tape, most of whom point towards the pains and costs of managing, transporting and storing data in such a facility. In addition, it can present challenges in ensuring that data is durable.

Many organisations need the data they archive today to be accessible and readable 15 or even 30 years from now, which is why tape’s decline was staggered year-by-year.

Newer technologies offering greater flexibility, reliability, speed and total cost have replaced tape as a backup medium. Most restores are from the latest backup and so, for convenience and because the cost is so attractive, almost everyone stages their backup to a purpose-built appliance or to a NAS box.

Then, if longer-term or offsite backup is required, the backup can be moved to alternative premises or to the cloud.

Tape as a better disaster recovery medium

As a disaster recovery medium, tape has not been able to compete with the convenience of disk. It has also struggled as a cold storage medium, since access times are prohibitive – and optical storage prevails as the most durable and reliable for very long-term archives where the volume of data is not excessive.

However, for medium-term retention of a very large vault – where access times of hours or days are acceptable – tape has continued to dominate.

‘In the specific situation of being able to store the data in dark environments, with temperature and humidity control, without the costs of spinning disks, the benefits of tape outweigh those of alternative media types,’ says Joe Fagan, EMEA senior director for cloud initiatives and kinetic at Seagate.

‘However, businesses are increasingly turning to other technologies to suit the ever-changing storage needs and cost pressures that they face.’

This has left tape lagging behind. Tape backups are less than 100% reliable, and organisations should expect no better than a 98% success rate for restoring data on this format, particularly if it has been brought back from off-site.

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If the organisation can survive three or four days without any IT service with minimal or no business impact, then recovery from tape backup is a viable option.

‘The good news is that the cost and complexity of implementing disaster recovery (DR) to meet sub-24 hour recovery times and recovery points is reducing,’ says Richard Blanford, managing director of Fordway.

‘Virtualisation is making services more portable, and SAN and application replication gives better options and more reliable recovery methods than tape.’

DR solution needs to be driven by the needs of the business

There is also a range of hosted and cloud DR options available. Before deciding on a solution, it’s vital that the business is asked the right questions first, as the DR solution needs to be driven by the needs of the business.

Blanford adds, ‘In what order should services be restored? How quickly are they needed? The most important thing is to have a backup and recovery plan that is realistic and proven.’

Archives today are increasingly treated as active data sources rather than just cheap storage for data resiliency. As such, tape simply cannot meet new compliance and e-discovery requirements and the expectations of a demanding mobile workforce, according to Dan Sloshberg, cloud archiving expert at Mimecast.

‘Speed of access is now so important that businesses replacing on-premise archives with cloud services should also demand service-level agreements (SLAs) for search queries on archived data,’ he says.

But not everyone is so critical of tape. Spectra Logic CTO Matt Starr, for example, believes there is always need for an air-gap between live data and the backup data. 

As seen with the recent attacks on Sony, data on the drive can be destroyed, meaning that data backed up on disk can also be deleted. 

Breathing space

Tape is one of the few media that give such an air-gap between the read-write-delete command and the actual data.

‘Off-site tape provides even more protection, including natural disaster,’ says Starr. ‘For small sites, cloud-based backup may be a good vehicle for backup and archive, but, yet again, if the hacker can reach it then they can delete it.

‘In the end, there will always be a need for a very low-cost storage media that can hold data for a long time, protect it from hacking and enable easy recovery. Today that media is tape, and for the future the roadmap for tape looks very promising.’

Organisations must also not be too quick to assume that cloud is the best option for them. Amongst all the industry hype, it can be easy to succumb to hyperbole.

Really, it depends on the size of the organisation. For smaller businesses, cloud may provide a cost-effective way to store backup or archive data.

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‘The current model is about a penny per gigabyte per month for very cold cloud storage,’ says Starr. ‘This storage has an SLA of about five hours before data can actually be transferred back to the data centre.’

When you begin to scale this type of storage, the price per gigabyte per month model falls down fairly quickly. Also, this does not include the in-and-out charges that can really spike the cost of cloud storage.

‘If a company has less than 100 terabytes of stagnate data that it needs to store, cloud may be a good option,’ Starr adds. ‘If, on the other hand, it has 200 terabytes of semi-active data and that is growing at 40% to 60% per year, it will soon be paying the cloud provider the same amount of money every six months that it could have spent on purchasing a tape archive and keeping it local.’

A new dawn

While many may still be keen to see the end of it, tape storage is facing a new dawn in a world that is struggling to get to grips with the impact of big data, environmental pressures, complex IT infrastructures and resource limitations.

With the new developments, tape may well rise to once again become the best available method of storing data.

‘Tape is widely supported and has a mature interface, enhancing the long-term compatibility of its stored data,’ says Phil Greenwood, commercial director at Iron Mountain. ‘Our world is powered by information, and how and where we store it has become mission-critical. Tape belongs at the heart of that conversation.’