February 2007 — News
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Data Protection: Make a Wise Decision
Removability and portability are important elements of the backup destination. Whichever media is chosen, portability is important. Since backup is a disaster recovery (or business continuity) tool, the responsible party should be able to remove critical data from the main building location at some point, where earthquake, fire, flood, or even a human might take a toll. Whether it is stored in a bank vault or a financial officer's closet, portability creates an extra level of protection for that valuable information.
Cost is an issue, an assertion that comes as a surprise to nobody. In calculating cost, it is best to include the platform, the destination, the time spent in backup versus the time it would take to rebuild lost data in a data outage situation, staff time investment and any relevant overhead costs. But small and midsize organizations are the darlings of the computer storage industry right now, with storage vendors competing aggressively for their dollar like never before.
One of the advantages of current backup technology is that there is both the freedom and the burden of choice. But a careful examination of the different destination media will chart a course to the optimum SMB destination: removable disk.
The well known compact disc is an optical disc capable of storing data, although limited to a capacity of 650 MB to 850 MB. CD-ROM is a common format for software distribution. CD's first cousin, the DVD, is visible in the data storage market as well, and while the capacity is higher than that of the CD, it is still limited to between roughly 4.2 GB and 8.5 GB. They claim to offer long service life and a comparatively low cost. But capacities are more limited than most magnetic storage solutions, and I/O speeds may not fit in with the backup window. Additionally, CD media is fragile; scratching the surface loses data. DVD media is resistant to scratches, but is limited to a single level of error correction, casting a cloud on its reliability. And recordable CD and DVD media will degrade over time.
Tape has been the workhorse of backup for 50 years. Tape drives have data capacities of anywhere from a few hundred kilobytes to several gigabytes, and varying transfer speeds as well. While tapes are a very portable removable storage solution, the disadvantage of tape drives is that they are sequential-access devices, which means that to read any particular block of data, you need to read all the preceding blocks. The wait to restore essential files in a disaster recovery situation would be unacceptable to many schools, for whom fast restore time can be of the essence in keeping things going. This tape limitation is being recognized by OEMs, such as Dell, who are phasing out low end tape solutions with limited roadmaps (such as DDS) as part of their offerings.
Longevity of the media is also an issue: it is customary to relocate data to fresh tape every five years or so, and users often discover upon data recovery that the backup did not complete. Additionally, newer drives can be very costly, and might break the available budget.
