ekzman - Fotolia
Tape storage: Four key reasons why tape is key to storage strategy
We look at tape storage and examine its benefits in capacity, throughput, suitability for certain media types and workloads, as well as its cost and security advantages
Magnetic tape is seeing something of a revival as a storage medium. The need to protect data against malware, as well as renewed interest in disaster recovery and business continuity, have put tape back on the agenda.
But then, tape never really went away.
Tape was the mainstay of data storage from the 1960s to the 1980s, but it was supplemented and then largely replaced as primary storage by hard drives and later solid-state drives (SSDs).
Tape, however, stayed on as a low-cost medium for offsite backups, archiving, and managing large files in industries such as media production. And tape retains some unique characteristics that are hard to replace with other storage media, even as tape systems themselves develop, and firms look for new uses for archived data.
Here, we rewind back to some of tape’s key attributes.
What capacity, capabilities and standards does tape offer?
A tape system’s capacity is, theoretically, unlimited. Users can simply write to more cartridges. The constraints are usually time, budget and physical storage space.
In practice, however, tape storage cartridge capacities have improved steadily, as have read/write times. The first generation of linear tape-open (LTO), from 2000, held 100GB of raw data, or 200GB compressed. The current LTO-9 can hold 18TB natively, and 45TB of uncompressed data. The LTO roadmap sees these capacities increasing up to 576TB of native data, and 1.4PB with compression, under LTO-14.
These improvements make backup or archiving for large storage arrays or databases possible on a single cartridge. And modern tape is – relatively – fast, able to read compressed data at up to 1,000MBps.
Nonetheless, tape has some technical drawbacks. It is a linear media, so is less efficient at random input/output than other media. Tape systems are also mechanical, so more prone to failure than SSDs. Large tape libraries feature mechanical handling systems, which users must also maintain.
Then there is the need to care for the tapes. In theory, a tape will last for 30 years, but cartridges must be stored at the right temperature and humidity and, if firms want to secure their data, under lock and key.
The main standard for tape storage is LTO and most tape suppliers support the technology. Meanwhile, the Ultrium format is supported by IBM, HPE and Quantum. Digital linear tape remains in use and supported by Quantum Sony, Fujifilm and Maxell.
Tape vs the rest: How do the costs stack up?
Tape systems, especially libraries, can be expensive to buy. But, tape media itself is cheap, and running costs are low. According to businesses that use tape, systems can be as much as 80% cheaper than spinning disks. And, as a tape cartridge uses no power when it is not in use, energy costs are lower too.
Darrel Kent, field chief technology officer at analyst GigaOm, said: “At scale, tape typically delivers an order of magnitude lower cost per terabyte compared to spinning disk, and often two orders of magnitude below active cloud storage – especially once you include power, cooling, and refresh overheads.”
It is, therefore, arguably the most efficient of storage media, he added.
“It’s sequential, scalable, and stable,” said Kent. “Where other media can struggle with power, cost, and long-term reliability at petabyte scale, tape is the medium whose performance improves with volume. You can get more efficiency, not less, as archives grow.”
LTO-9 tapes cost around $85 for 18TB of native storage. Tape drives and libraries cost between $5,000 and $15,000 depending on capabilities. LTO-8 tapes are cheaper.
Calculating a specific per TB storage cost for tape, however, is hard as it is removable media. Much depends on whether businesses reuse tapes, or store them permanently off-site. Meanwhile, Archiware, a data management vendor, has compared the cost of tape against cloud storage for a number of scenarios. It found a standalone LTO system cheaper than cloud storage for users archiving 50TB and up each year, but LTO libraries are typically more expensive than the cheapest cloud options.
What are the security benefits of tape storage?
Tape costs, however, can be less important than issues of data security and sovereignty.
Tape users know exactly where their media is, and that’s something that cannot be said for cloud storage. And tape is the ultimate “air-gapped” storage solution, provided of course that cartridges are taken off-site and held securely. There is also no data loss if a tape drive fails.
Enterprises have come back to tape in part because ransomware gangs started to target backup software and backup volumes. That’s because ransomware cannot infect an offline tape. In addition, standards such as LTO include write-once-read-many data protection, so malware should not be able to overwrite or encrypt backups.
For this to be effective, IT teams need to maintain good hygiene and physical security around their backups. But if they do, tape provides a strong line of defence.
What are the key use cases for tape storage?
Tape storage is well-suited to large volumes of data that need long-term storage. Archives are perhaps the next most common use for tape after backups.
Tapes have other uses too, such as storing media files, including entire cinema productions, and scientific and medical data. Cern, for example, is a well-known user of tape, and uses it to store more than 1.3EB of data. This is expected to grow to 4.3EB by the next decade.
Tape, especially tape stored off site, is the ultimate “cold” storage. Long-term archiving is increasingly important for enterprises, as they keep data for longer for compliance reasons, as well as for business intelligence and artificial intelligence. Even the hyperscale cloud providers make use of tape in their datacentres.
This trend could even lead to an increase in organisations’ use of tape, with air-gapped, offsite storage for security and near-line storage in on-site tape libraries to allow enterprises to access, and reuse, their archived data.
Read more about tape storage
- Storage technology explained: Key questions about tape storage. We look at the benefits of tape storage – low cost, inherent security, excellent energy efficiency – the workloads it is best for, and how tape fits a wider storage strategy.
- Air gaps for backup and how they help against ransomware. The air gap is a basic of backups and storage. We look at what’s meant by an air gap, the rise of the logical air gap, and its place in the fight against ransomware.
