Disk space is an important part of any enterprise data storage strategy, but it is simply not practical or even desirable to use disk exclusively for all of your enterprise storage needs.
Enterprise storage is not an “either/or” proposition. Flash storage, disk, and tape all have their place in an enterprise tiered-storage strategy, and you have to use the right tool for the job. Flash storage is ideal for tasks with intensive I/O requirements where speed is the most critical factor. Disk works best for primary storage and as a staging area for backups. And tape is ideal for backups and archives.
Many storage vendors paint tape storage as an inferior solution to disk, a last-generation technology on the verge of extinction — a dinosaur, if you will. But the reality is that tape storage is not a dinosaur. Tape storage continues to be a key component in the enterprise data center, and most of the world’s information is actually stored on tape! This has been true for many years, and will be well into the future. Tape also has better error correction rates and longer refresh cycles than disk.
Finally, tape has a significantly lower total cost of ownership(TCO) compared to disk. The cost and performanceadvantages of tape include
✓ Acquisition costs. The Clipper Group (www.clipper.com) estimates that the cost to implementa disk-based archive is 15 times more thanthe cost of a tape-based archive.
✓ Energy savings. An enterprise-class tape libraryuses much less energy (290 times less accordingto the Clipper Group!) than disk because it doesn’tspin 24/7 like disk. In a 2010 study, the ClipperGroup concluded that the cost of energy alone forthe average disk-based solution exceeds the entireTCO for the average tape-based solution.
✓ Management savings. Tape has a higher ratio ofpetabytes managed per storage administratorthan disk. This translates to lower overall laborcosts.
✓ Longevity. No matter how you store your data,eventually it has to be moved either due to obsolescenceor deterioration of the storage media. Itis not uncommon for archive data to remain on tape for up to a decade (though the tape itself canlast up to 30 years) — disk archives typically needto be replaced every three to five years.
✓ Scalability. Tape storage systems are highlyscalable — simply add more tapes for additionalcapacity and more drives for performance. Theamount of tape and capacity that can be stored ina tape library dwarfs the capacity of comparabledisk storage systems. Thus, you get more petabytesof storage per square foot in the datacenterwith tape than with disk.
✓ Data integrity and auditing. Assuming the data isgood when you archive it and the storage media isproperly maintained, with tape, WYSIWYG (whatyou see is what you get) becomes “what you storeis what you get.” But disk is constantly subject tocorruption due to bad sectors, disk failure, malware,or accidental overwrites.
Myth #1: Tape is more expensive than disk.
Tape costs lessper terabyte, consumes less energy, and is less expensive tooperate than disk.
Myth #2: Tape is cheaper to buy, but more expensive tooperate.
The Data Mobility Group reports the TCO for a SerialATA-based disk storage system is 11 times higher than anLTO-based tape configuration over a seven year period.
Myth #3: Tape has gone away; no enterprise data centeruses it.
Most enterprise organizations use a tiered storagestrategy with tape as the foundation layer, and nearly half ofthe world’s data is stored on magnetic tape.
Myth #4: Tape is unreliable.
The bit error rate (BER) forOracle’s enterprise tape products is more than 4 million timesbetter than enterprise disk.
Myth #5: Tape is a greater security risk than disk.
Tape isdesigned to be portable and therefore has a higher potentialfor loss.
As a result, tape encryption became a necessity longbefore other storage media encryption and is far moreadvanced.
Tape encryption is built into the tape drive andruns without performance degradation.