This article is part of our special IEEE Journal Watch series, presented in collaboration with IEEE Xplore.
According to a Berkeley National Laboratory analysis, data storage has historically contributed a large percentage of the computing industry’s carbon footprint, accounting for as much as 1.8 percent of overall electricity use in the United States in 2014. Brad Johns, a data-storage consultant in Arizona and a veteran of IBM’s data-storage company, believes that the solution to data-storage sustainability resides, at least for the foreseeable future, in a piece of technology that many may consider already obsolete: magnetic data tape.
“Many firms have an opportunity to minimize their carbon footprint and do it in a cost-effective manner…. “It’s a win-win situation,” says Johns.
At least 60% of all data is “cold,” although it is still stored on hard disks. This presents an opportunity to switch to a greener—and less expensive—alternative.
The demand for data storage is also increasing. According to International Data Corp. (IDC), the total quantity of data created will increase from 33 zettabytes in 2018 to 175 ZB in 2025, with approximately 10%, or 17 ZB, of that data being stored in 2025. In 2021, according to IDC and Seagate forecasts, 62 percent of data is kept on hard disks, 9 percent on solid state drives (SSDs), and 15 percent on tape.
Hard disks are more handy for storage since information can be retrieved considerably faster from them than from tape storage. According to Johns in an article for Motion Image Journal, the trade-off is higher carbon emissions—hard disks have a life span of about five years, during which time they produce around 2.55 equivalent kilograms of carbon dioxide per terabyte per year (based on a Seagate estimate for the Exos X18 hard disk). Tape medium, on the other hand, has a life period of more than 30 years, during which time it emits only 0.07 kg CO2/TB/year (based on a Fujifilm estimate for the LTO 9), or 3 percent that of hard disks.
Carbon is saved by using tape storage.
According to Johns, the vast majority of the information created and kept today is “cold data,” or material that is rarely accessed but nevertheless has value and cannot be deleted. According to IDC’s 2019 white paper, 60 percent of all data is cold yet still exists on hard disks. According to Johns, this creates a significant opportunity for large data firms to convert to a more sustainable form of data storage, tape storage, which would minimize their carbon footprint.
If enterprises worldwide migrated all of their cold data, or 60 percent of all data, to tape, the amount of carbon dioxide released by data storage globally would decline by 58 percent, resulting in a 79 million ton reduction in CO2 emissions, according to Johns.
Reducing Electronic Waste
Tape storage helps to reduce e-waste.
Transferring cold data to current tape media decreases electronic waste (e-waste). Because hard disks have a five-year life expectancy, the old ones must be discarded in order for the new ones to preserve the same data. Because tape storage is routinely changed every ten years, there is less discarded storage. For example, if a data center wants to store 100 petabytes of data for ten years, storing all of the data on hard disks generates 7.4 tonnes of e-waste. If 60% of the data is transferred to tape, only 3.6 tonnes of e-waste are generated, resulting in a 51% reduction.
“Tape has a clear advantage over hard disk drives today.” And, based on the road maps, it’s likely to stay that way for the next decade.”
—BRAD JOHNS, CONSULTING BRAD JOHNS
According to Johns, the financial reward is an additional motivation for this strategy. Using Fujifilm’s total cost of ownership (TCO) tool, he found that storing all 100 PB of data on hard disk costs US $17,707,468, whereas a mix that contains 60% tape reduces the cost to $9,476,339.
Many large organizations have already begun to migrate to tape storage. However, the transition to tape has been slower for smaller businesses. The concept of cold data varies depending on the demands of particular companies and user requirements. As a result, classifying data as “cold” so that it may be moved on tape is difficult–and it takes time, money, and effort. Large firms may have these resources, but smaller businesses might not. This is one of the barriers to the widespread use of tape storage in smaller-scale data centers.
The managerial difficulty is another barrier that Johns mentions. “The technology is fairly well established. “It’s just trying to get the momentum going in the midst of everything else that IT organizations have to do,” he says.
Regardless of whether organizations adopt the solution, the question remains if tape storage is a viable option. “Tape today clearly has a compelling advantage over hard disk drives, and if you look at the road maps, it’s probably going to stay that way for the next decade,” adds Johns. However, alternate research is ongoing. According to him, Microsoft, for example, has invested in research for DNA-based storage possibilities. “There’s still a lot of research and engineering to be done to actually turn it into something,” he says.
