The majority of data is very seldom accessed. The old 80/20 rule still applies today. Twenty percent of the data is accessed eighty percent of the time. The other eighty percent of the data is not accessed very often. The need to store data for a long period of time, coupled with the knowledge that much of data will be infrequently (or never) accessed helps to define one of the new roles of tape in the data center.
The Evolving Role of Tape in the Data Center THE CLIPPER GROUP
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SSMM SM Explorer Navigating Information Technology HorizonsPublished Since 1996 Report #TCG2006111L December 31, 2006
The Evolving Role of Tape in the Data Center Analyst: Dianne McAdam
Management Summary The disk versus tape debate continues to rage within the trade publications. Disk supporters claim that the emergence of low cost Serial ATA (SATA) drives proves that disk is now a viable, inexpensive media for backup. In fact, some proponents claim that tape is dead.or at least dying. The very eloquent writer, Mark Twain, once said, "The rumors of my death have been greatly exaggerated." Tape vendors could say the same thing - the rumors about the death of tape have been greatly exaggerated. Tape is neither dead nor dying - but the role of tape is changing within the data center. It is said that some things don't change very much in IT. It does seem that the disk-versus-tape debate has not changed over the last several years. The prices of disk drives are dropping, making disk an attractive option for some traditional tape-based applications. Nevertheless, tape vendors continue to develop and deliver larger tape cartridges, reducing the cost per gigabyte. Therefore, the gap between the cost of tape and disk remains the same. But some things do change in IT. Enterprises, both large and small, are now faced with a new challenge - the challenge of storing more and more data every year. Enterprise data centers report data growth rates of 50 to 100 percent or more. Unstructured data, such as digital images, is growing at a faster rate than structured data (such as databases) and these unstructured files can be very large. For example, if we stored the complete works of Shakespeare, we would need five megabytes (MBs) of storage. Five MBs is also the average size of just one digital photo. Not only are we required to store more and more data, but also we have to keep it longer than we did before. Regulations require financial companies to keep emails for seven years or more. Health care agencies are keeping records for the life of the patient and longer. The result - storage requirements are growing at extremely high rates every year and there appears to be no end in sight. IT is responsible for storing lots of data for a very long time. But how often do we need to access that data? The majority of this data is very seldom accessed. The old 80/20 rule still IN THIS ISSUE applies today. Twenty percent of the data is ¾accessed eighty percent of the time. The other The Evolving Role of Tape and Disk..... 2 ¾eighty percent of the data is not accessed very What Tape Does Well ............................. 2 often. The need to store data for a long period of ¾ Comparing the Acquisition Costs time, coupled with the knowledge that much of of Disk and Tape ..................................... 3 data will be infrequently (or never) accessed ¾ Comparing the Electrical Costs helps to define one of the new roles of tape in of Disk and Tape ..................................... 4 the data center. ¾ Other Factors .......................................... 5 Read on to examine the new roles of tape ¾ What About Data Reduction? ................ 5 and disk in data centers today. ¾ Conclusion .............................................. 5
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The Evolving Role of Disk and Tape adding cost but also because you only need to Disk drives were originally designed to sup- recover from disk for a short period of time. Older port random I/O operations. They have been and disk-based copies of backups can be migrated to continue to be the right storage device for online tape, freeing up disk space to store more backups applications that require fast access. that are current. The explosion of internet commerce has Writing backups to disk (disk-to-disk), then required some applications to be available 24 migrat... [download for more]
