Storage technology explained: Key questions about tape storage

What are the benefits of tape storage?

Tape storage has several advantages over other storage media, but some of these attributes are also its disadvantages.

First, tape has almost limitless capacity. Tape cartridges are larger than hard drives but their capacity is greater, they can be swapped out for offline storage, and use autoloaders or library systems to store much larger volumes.

Tape also lasts longer than HDD, with a lifespan of up to 30 years, in a well-controlled environment. HDDs can expect to last between three to five years.

Tape’s atorage capacities are already impressive. Another advantage is that unlike HDDs, tape systems consume little power when not in use. A tape cartridge stored offline uses no power at all, aside from whatever is needed to keep it in a temperature-controlled environment.

Because organisations need to account for IT’s carbon footprint, this is important. CERN, which uses LTO tape, calculates that tape used 2% of its datacentre power consumption in 2021 while spinning disk used 21%. Aardman Animations, another LTO tape user, says it saved 80% in costs compared to hard disks.

A further advantage is that tape creates a physical air gap, which provides a critical line of defence against ransomware. It is easy to move tapes to an offsite location. Modern tape libraries can write multiple copies at once, which allows firms to keep on-site and off-site copies. Data on tape is safe, provided users do not re-mount it on an infected system.

What capacity can you store on tape storage?  

Tape storage offers the possibility to store vast amounts of data. SpectraLogic’s TFinity Plus, announced in April 2024, promised capacity that heads towards 2.5 exabytes, with compression.

Tape libraries comprise many individual tape cartridges, of which the current generation LTO-9 tape offers 18TB of raw capacity, rising to 45TB with compression. LTO-10 – due in Q2 2025 – promises to double that, with LTO-14 (due in 2036) set for 576TB of native storage per cartridge and 1.4PB with compression.

What are the disadvantages of tape storage?

Tape does have some downsides. First and foremost, it is a mechanical medium and one that has limited support for random reads and writes.

To access a specific data point on a tape – say a file or database record – the system needs to move the tape until the relevant part can be read by the heads. But in some use cases, tape can compete with hard disks, although flash media will always be the best option where I/O performance is key.

Another disadvantage is the potential fragility of tape media. Tape systems, especially auto loaders, are mechanical devices and these need to be maintained. And though tape does not need power when it is offline, cartridges do need to be handled with care and stored in a clean, temperature-controlled environment to maximise their life. Tapes also need to be checked periodically for degradation.

What workloads are best for tape storage?

Backup, archiving and cold storage remain the most common applications for tape. A tape copy is still part of many enterprises’ 3-2-1 backup strategy, and backup applications now typically support tape as part of a tiered storage approach.

“Almost everyone has done a lot around making sure that tape is not just an afterthought, but a key part of their software and management platforms,” says Freeform Dynamics analyst Tony Lock.

This allows firms to expand their use of tape beyond backup and archiving. Long-term archiving and “cold storage” remain the other common application for tape. Even the cloud hyperscalers use tape as part of their storage infrastructure.

Is tape storage good for active archiving?

Changes to tape technology have allowed more organisations to move towards “active archiving”, where data remains in long-term storage but is still reasonably accessible.

Active archiving has a number of applications, including compliance, scientific research, machine learning and training AI models. Aardman, for example, uses tape to keep copies at each key stage of production for its animated movies.

“It’s not just using tape for long-term, cold storage, but for warm storage. You might not use it every day, but when you want to access it you want to access it reasonably quickly,” says Lock. “You could look into the system for what happened 15 years ago.”

Is tape storage good for reading streaming data?

A further use case for tape is to store large data files, or continuous streams of data, that are read sequentially. Applications here include media streaming as well as scientific, research or medical data. In these cases, tape comes close to disk for continuous read speeds, but at a much lower cost.

What is LTFS?

LTFS – Linear Tape File System – is a file system-style record of files on tapes and so gives NAS-like access to data. This means applications and users can copy to and from tape using drag-and-drop or other standard methods of data movement.

Around since 2010 with LTO-5, LTFS has allowed access to tapes as if they are disk drives. LTFS partitions the tape, with one containing indexing information for all the data on the cartridge and the other the actual data. With this capability married to a hardware NAS protocol front end and disk cache and you have the potential for rapid access to massive amounts of data held on tape.

Vendors with LTFS products include, IBM, Fujitsu, Nodeum, Quantum, and SpectraLogic

How does tape storage fit data storage strategy?

Any organisation that has a mature storage management architecture with tiered storage will likely already support tape.

For applications such as archiving – with cold and warm storage, and especially active archives – end users are unlikely to know their data is on tape. Data management software should manage movement of data between storage tiers and minimise any delays during location and loading of tapes. Systems such as LTFS (see above) speed up the process of locating data.

Such developments also make it easier for software developers to tap into tape systems. A business intelligence or CRM system could, for example, retrieve data directly from tape. Meanwhile, backup tools, with an increasing focus on ransomware protection, integrate tape for off-site backups.

Firms might also want to use tape alongside or as an alternative to cloud storage. Cloud has its advantages for long-term data storage, but data egress fees mean retrieving data from the cloud can be costly. Modern tape systems are a viable alternative for organisations that prefer to keep at least one copy of their long-term data in-house.