Disk vs. Tape: Which One’s Game for the Long Term?

Topics: Offsite Tape Vaulting

So it's a battle you're looking for, eh? Disk versus tape is a great one to check in on: Ultimately, one will assume the "Long-Term Data Protection" title.

Like any two boxers that step into the ring, each format has its advantages and weaknesses. Still, there's one clear winner for your extended data backup and recovery requirements: tape. Check out these scorecards to find out why.

Contender #1: Backup Tape

In this corner is tape, a system that's seen a lot of opponents come and go. Don't assume that means it's long in the tooth, though. Like Bernard Hopkins, who at 46 became the oldest boxer ever to win a world title in 2011, tape still packs a punch. Why else would thousands of enterprises still be tapping the powers of tape backup in today's digital world?

Consider backup tape's advantages:

  • Tape provides high-capacity storage. LTO (linear tape-open) is the leading tape backup format. Its latest iteration, LTO-6, hit the market in late 2012 and offers 2.5TB of storage. When using improved compression (2.5:1) features, an enterprise can store up to 6.25TB of data on a single tape. Not bad for an aging technology.
  • Tape is your partner in policing overhead. Tape media costs are low—in fact, tape is the least expensive option for enterprise storage needs. Compare tape to a disk array with the same data capacity and you'll find that tape wins in price every time, even when you factor in the costs of offsite tape vaulting.

Tape really steals the show when you calculate the energy that each format uses—once an enterprise stores its data for the long term, it no longer requires electricity. Disk systems, on the other hand, are always on and require constant cooling.

  • Call it "Old Reliable." You use a tape only when transferring data to it.After that, it sits on a shelf. In contrast, disk data backup systems are constantly whirring, buzzing and humming. Which sounds more prone to breakdown? That's right: disk.

Know tape's challenges:

  • You'll spend more time seeking your data. Backup tape's seek time improved greatly with the introduction of LTO-5's LTFS (linear tape file system). LTFS makes tapes more like disks. This technology doesn't need to search through all of a tape's contents to find what you're looking for; rather, it goes right to it. However, LTFS alone can't make tape faster than backup disks.
  • Maintenance remains key to durability. Tape requires attention. This media must be kept in a pristine environment to prevent error-causing dust or dirt from getting into those cartridges. And tape cartridges are not going to label, log or test themselves. This isn't difficult to do, but it can be tedious and time-consuming.
  • It's a longer road to recovery. If the files you need to recover reside at an offsite tape vaulting service, it will take longer to get that data back. That's why you should opt for backing up and storing frequently used, business-critical information in-house.

Clearly, the advantages of the format are as sturdy for the long run as our champion Hopkins. As for the challenges, they're not likely to pose any significant issues when you're talking long-term data storage needs. For long-term storage, Priority No. 1 is simply having your data backed up as a hedge against emergencies and to remain compliant with laws and regulations.

Explore Best Practices for Tape Backup and Recovery

Tapes are sturdy, but they still need care for dependable results. Consider adopting these procedures for your enterprise:

  • Regularly and vigorously test your tape data backup system to ensure it works correctly and can restore your critical data. When is the worst time to test your backup and recovery procedure? After a major disaster.
  • Don't hesitate to retire a tape that's past its prime. Getting one or two read/write errors doesn't mean a tape is bad. A little dust where it shouldn't be can cause the occasional error. But if a tape begins having errors daily, it's time to retire it.
  • Upgrade to newer tape systems as technology advances. While it might seem a burden to go from an older LTO-4 system to a new LTO-6, the improved features and capacity of newer tapes will deliver real productivity savings.

Contender #2: Disk Systems

On this side of the ring are disks, which don't require the maintenance of tapes and scale easily. Disk looks at tape and sees some crazy old boxer whose prime years are behind him. But it's got it all wrong. Tape sees disk backup as the young boxer who comes out swinging but can't go the distance.

Consider disk backup's advantages:

  • You'll enjoy rapid recovery. Finding a particular file with a disk system is faster than with a tape data backup system. Plus, enterprises tend to put disk systems to work in-house, so you'd never have to ship in your data from an offsite storage partner.
  • Disk achieves high-level security. One undeniable virtue of disk-based data backup solutions: A data center is hard to misplace. You need not worry about secure data transportation, because the data's not travelling anywhere. (However, a firm choosing a tape backup system should thoroughly vet potential third-party offsite tape vaulting partners to avoid any security mishaps.)
  • You'll gain efficiencies from deduplication. This process removes duplicate copies of saved data to free up space. Deduplication means you can store data more quickly and perform full backups less often.

Know disk's challenges:

  • You'll pay for convenience. Disk systems are constantly on—and constantly on the verge of running hot. That means you not only have to power them, you also have to power cooling systems to keep them from overheating. If you're thinking of investing in a disk-based data storage system, be sure to total all the costs first.
  • In-house storage comes with compromises. An onsite disk system eats up a great deal of space and energy. Being able to dedicate that real estate to other needs by sending less-used data to offsite vaulting for long-term storage is a big plus for tape data backup systems. Plus, it's good to have critical data stored offsite in case of a fire, flood or other disaster.
  • Overwriting comes with perils. Newer LTO tapes use WORM (write once, read many) security that prevents accidental overwriting from ever occurring. Overwriting is more of a risk with disk systems, since the entire disk could be accidentally reformatted. When that happens, you'd better either have a redundant disk on hand or your resume in order.
  • Get your head out of the cloud. If you're reading this and wondering "What about cloud storage?" know that it also has significant weaknesses. For large data needs, cloud offers slower retrieval times and higher costs than you'll get with tape. Cloud may be useful for newly created and frequently used data (tier 1 of a tiered storage system), but not currently for Big Data or archiving.

The Judges Weigh In

Considering disk pros and cons should make it clear: An in-house disk system—or even cloud storage—can work for recently created and/or frequently used data. But for long-term storage and access, you can't afford to be without reliable, cost-effective tape data backup, preferably stored with an offsite tape vaulting service.

Iron Mountain Recommends: Plan Your Recovery

Plan for data recovery long before a calamity hits your company. This isn't just planning for a rainy day: We're talking torrential floods, a tornado, or maybe an earth-shattering audit. Follow these steps to ensure you're well prepared:

Create a tape archive and have an offsite data vaulting service host it. This will ensure not only that you have your critical information backed up, but also that it's out of harm's way. Make sure your partner offers disaster recovery support.

Set realistic data restoration expectations. Data restoration for all of your company's vital data will take some time. Have a realistic schedule in mind. When you get overly ambitious, you'll only rush the process and invite errors.

Test, test, and test. When it comes to restoring all your company's data, one test isn't enough. Test your data backup system regularly throughout the year. You want to make sure that you and your team know the procedure, and that your process is optimized and efficient.


Do you have questions about data backup and recovery? Read additional Knowledge Center stories on this subject, or contact Iron Mountain's Data Backup and Recovery team. You'll be connected with a knowledgeable product and services specialist who can address your specific challenges.


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