Rising power and cooling costs make energy-efficient storage media such as tapes and optical media look favorable, but power is not the only factor to weigh when choosing an archive solution.
From a power and cooling perspective, offline and nearline media such as tape and optical storage have a significant advantage over hard-drive-based archive solutions. Tapes and optical media do not consume power or create heat when they are not in use, so their negative impact on the data center environment is considerably less than hard-drive-based archives, where disks are constantly spinning and releasing heat.
At larger companies, where hundreds of terabytes and even petabytes of data need to be archived, the cost of keeping a disk-based archive spinning and cooled can easily reach tens of thousands of dollars a year.
However, while energy consumption is certainly a significant issue—and one that will only increase in importance over time—power concerns must be weighed with a number of other factors when evaluating various archive solutions.
During the life of an archive platform, maintenance, media, software licensing and IT manpower costs can dwarf the amount of capital spent on power and cooling. Large companies that already have either a disk- or tape-based archive need to evaluate the costs of switching to a different solution, with an emphasis on resources needed to retrain IT staff and users.
With compliance initiatives forcing virtually all companies to store data for several years, archives can easily multiply in size several times. Regulatory mandates, therefore, increase not only storage capacity requirements but also the cost of keeping data live and accessible.
Indeed, when developing or updating an archive solution, the factor that should trump all others—including power consumption—is a companys data accessibility needs.
Tape is energy-efficient, but load and seek times are the Achilles heel of tape-based media, making users wait minutes or even hours if a significant queue builds up for data. Disk-based archive solutions are energy hogs, but they are fast.
In the end, hybrid solutions that mix the accessibility and availability of disk with the cost savings of tape are usually the most efficient all around. By leveraging storage management tools, IT managers can determine data usage patterns to make sure data is moved to tape only when it is unlikely to be recalled.
With a hybrid disk archive/ tape system in place, IT managers can provide high-speed access to a portion of their data on a disk cache, ensuring that users dont have to wait for critical data, while still reaping the power savings of tape storage on the back end.
Solutions such as Sun Microsystems Content Infrastructure System efficiently mix tape and disk storage into a content archive, leveraging Suns proprietary SAN (storage area network) file system.
We hope vendors will accelerate the standardization of data migration protocols to create open archive solutions, giving IT managers even more options. However, considering the snails pace at which the storage industry moves, we wont hold our breath.
Senior Analyst Henry Baltazar can be contacted at firstname.lastname@example.org.