Tape backup—writing data to magnetic tape—is an older medium that has been around for decades. Data storage innovations from disk to flash to the cloud offering faster speeds, higher capacities, and more scalable solutions led many in the industry to declare tape obsolete as far back as the early 2000s. But tape usage continues to play a part in enterprise digital storage. As organizations experience exponential growth in their data needs and seek affordable means of storing large volumes of data, its usage is even expanding as more enterprises recognize its benefits.
This article explores the advantages and limitations of using tape, use cases for when it makes sense, and best practices to successfully integrate it into an enterprise data storage regimen.
- What is Tape Backup?
- How is Tape Used Today?
- Tape Backup Advantages
- Tape Backup Limitations
- Use Cases for Tape Backup
- Best Practices for Tape Backup
- Bottom Line
What is Tape Backup?
Tape backup involves sending data from enterprise systems to a tape drive or tape library where data is written to magnetic tape contained in cartridges. In small operations, the tapes have to be manually loaded, ejected, and stored. Larger operations take advantage of scale, automating the process and eliminating the need for manual intervention.
If you watch movies from the 1960s and 1970s that involve computers, you’ll see large reels of magnetic tapes spinning around—it used to be the main way to store data. As hard disk drive (HDD) technology advanced, businesses began to phase out tape as the storage medium of choice.
How is Tape Used Today?
Tape still plays a role in enterprise backup plans, but no longer the starring role. These days, tape backup is rarely the primary form—instead, data is initially written to disk or to the cloud, and either retained there or staged on disk for more rapid backup and then written to tape.
Alternatively, organizations using the 3-2-1 backup rule—make three copies of critical data, store it on at least two types of media, and retain one copy onsite and one copy offsite—will use tape as one of the storage media. It’s worth noting that many cloud providers also use tape.
Tape data storage occurs in a range of formats. Linear Tape Open (LTO) is currently the most popular format with significant investment from IBM, Fujifilm, and others, LTO has a roadmap many years into the future showing steady advancements in capacity, performance, and cost per TB. Other formats include Digital Linear Tape (DLT), Digital Audio Tape (DAT) and Advanced Intelligent Tape (AIT).
Tape Backup Advantages
Tape offers advantages over hard disk drives and flash—especially when it comes to storing large amounts of backup and archival data. Here are the most common.
A recent study into sustainability found the 10-year total cost of ownership (TCO) of 10 PB of storage and a 35 percent annual growth in capacity to be about eight times cheaper for tape than disk. Amazon Web Services (AWS), Google, and Microsoft Azure all make heavy use of tape in their cold storage tiers.
Disk Capacity Reduction
Organizations that keep all their data on disk see the price add up and power bills escalate. According to Storage Switzerland, enterprise backup repositories are typically 10 times bigger than ongoing production data—instead of storing a lot of data that may never be accessed on disk, organizations can switch it to tape and reserve disk for applications and data that demands higher performance.
Tape offers secure data storage—by retaining tape cartridges offline, disconnected from any network, they are immune to ransomware attacks and other unauthorized access. In addition, the Linear Tape Open generation 9 specification includes multi-layer security support with hardware-based encryption, immutable Write Once, Read Many (WORM) functionality, and fast data access with both the Linear Tape File System (LTFS) and Recommended Access Order (RAO).
A single LTO-9 tape cartridge can hold 45 TB of compressed data (18 TB native) with transfer speeds of 400 MB/s (native) or 1,000 MB/s with 2.5:1 compression—considerably faster than HDDs.
LTO operates at areal densities about two orders of magnitude better than the latest HDDs—when compared to an 18 TB disk, the latest 18 TB LTO-9 needs a small fraction of the areal density.
Moving cold and inactive data from disk to tape can bring about a reduction in carbon emission up to 97 percent, according to a Brad Johns Consulting study. Data centers consume around 2 percent of all electricity in the United States, and storage consumes about 20 percent of total data center power. Tape uses power only when data is being actively read or written; a tape cartridge on a shelf or sitting idle in a tape library consumes no energy, unlike disks, which are always spinning.
Data gradually starts to degrade on hard disk drives. Keeping data on disk for more than five years is asking for trouble—tape offers 30 years of longevity or more.
Tape Backup Limitations
Though tape offers many advantages, it also has some limitations. Here are the most common.
Initial Capital Cost
Most enterprises already have servers and disk arrays. Adding tape means investing in more hardware in the form of tape drives and libraries.
No Random Access
Data written to disks can be accessed from anywhere on the disk. Tapes, on the other hand, are accessed sequentially, which means it can take time to scroll through a disk to find a specific file to recover.
Slow Offsite Recovery
Offsite and offline tapes must be physically transported to where they are needed for recovery. This can add a day or two to recovery times, which may not be ideal for business continuity.
Use Cases for Tape Backup
Despite the innovation of several newer storage media, tape can still play an essential role in enterprise data storage. Here are the main use cases for tape backup.
Data archiving has become the main use case for tape because of its ability to affordable store data offline. As the drives only operate during reads/writes, they consume less power and generate less heat than disk storage devices. And, because the bulk of archived data might never be accessed, tape is more affordable than disk for data volumes over a couple of PBs. Organizations often find it best to keep hot production data that is 90 days old or less on disk and store the rest in a tape archive.
Active archives evolved as a solution to tape’s performance and speed drawbacks. The latest active archive solutions can keep tape-stored data online so it can be recovered rapidly—object or file restoration can be done in a matter of minutes. An active archive takes advantage of tape’s low cost, high capacity, longevity, and portability so that massive volumes of data can be maintained online for easy access.
Some businesses still use tape as their primary backup medium, often due to an existing investment in tape systems or IT team preference. In such cases, backups are usually staged onto disk before being moved to tape, offering faster backups without disruptions in mission critical systems or network overloads.
As ransomware attacks grow in frequency, tape becomes a more appealing option for maintaining a secure backup of mission critical data. Anything stored on disk or in the cloud can be infected; smart organizations store a copy onto offline tape to keep it safe.
Best Practices for Tape Backup
Tape offers many benefits for organizations that incorporate it into their larger data storage and backup strategy. But tape is not a set-and-forget solution—it must be administered, stored, and maintained appropriately. Here are some of the key best practices that should be observed.
- Test tapes regularly. Rather than dumping data onto tape and hoping for the best when it comes time for recovery, run tests that simulate a partial or complete data loss to measure how long recovery takes and how much data was recoverable. Adjust backup policies and procedures accordingly to improve results.
- Establish tape retention policies. Some companies endlessly store backups on tape after tape, which can add up; set a data retention policy on what tapes to retain and when to purge them.
- Keep technology current. Tape technology is still evolving, with a new generation out every couple of years. To keep systems backward compatible, retain old hardware even after upgrades.
- Maintain offline copies. Keep at least one full backup offsite at all times. In the event of a total site failure, that backup could save the day.
- Store tapes responsibly. Tape storage environments require minimal exposure to heat, humidity, dust, direct sunlight, and magnetic fields. Clean tapes regularly to keep them free of dust and dirt.
- Keep them organized. Create a tape labeling system and keep a log that covers what is on each tape and the date it was made.
- Enable security features. Modern tape systems typically come with security features. Be sure these are enabled to keep tapes encrypted, immutable, and free from malware. Physical security is also important—keep tapes locked up and only allow authorized access to them.
Despite newer players in data storage media, tape is anything but a dead or dated technology. In some areas, its roadmap of innovation exceeds that of disk. But it isn’t a case of disk versus tape—both play a role in enterprise data storage and backup and recovery strategies.
Each has its advantages and disadvantages, and in many cases organizations should deploy both. Business with small volumes might rely on disk alone, but for organizations with backup or archive capacity more than a few PBs, tape is a more affordable and more secure option.
Read our comprehensive guide to enterprise backup and recovery to learn more about what goes into a successful backup and restore strategy.