The Cost Of Doing Nothing

Cost containment seems to be THE word in storage right now. One of the options for containing costs is to archive old data off primary storage as described in our Archiving Basics article. A common thought, however, is that instead of creating a disk archive, just keep expanding primary storage. Isn't it cheaper to add a shelf of storage instead of developing a whole new storage tier?The basic assumption is that it is cheaper to do nothing than something, but the truth is you are really not doing nothing; you are weighing the cost of expanding your primary storage vs. the cost of building a disk archive tier from vendors like Permabit, Bycast, and Tarmin. At first, adding a shelf of storage may look like the cheaper alternative, but the ramifications of continued tier one build-out can be staggering.

First, by continuous expansion of tier one you are paying substantially more for disk capacity on a per-gigabyte basis. Disk-based archives are typically less than $3 a GB today after optimization. And primary storage, depending on your supplier, can be anywhere from $6 to $15 a gigabyte. Adding that one shelf may be less expensive in this instance, but the continuous adding of shelves is very expensive compared with establishing the archive tier.

This is not even a multiyear ROI. Typically, a complete archive system can be had for the cost of two or three shelves of primary storage and, once in place, archive's other payoffs kick in.

Other than the raw price advantage on a per-capacity basis, archiving also is greener than primary storage. Yes, even if that archive solution doesn't use specific power-savings features, with 1-TB drives commonplace in archive storage, and 2-TB drives right around the corner, the capacity per watt of archives is significantly better. Factor into this savings that most archive solutions have either compression, single-instance storage, or deduplication delivering a conservative 3X storage efficiency, and that capacity per watt improves even more.

The continued expansion of primary storage has a dramatic effect on the cost to protect the data it holds. When you add that shelf you are not really just adding an additional shelf. You more than likely have to budget extra capacity at the DR site for replication, extra capacity for the disk-to-disk backup storage, and extra tape capacity for the movement of the backup job to tape. An archive eliminates all these costs by moving data as it ages out of primary storage and, as a result, out of the replication and data protection paths.

Adding even that one shelf is expensive. Adding archive can free up as much as 80% of your primary storage right now, eliminating the need for not only this shelf purchase, but the next several as well. It also reduces power consumption and reduces costs throughout the data protection process.

View our Webcast on Primary Storage Optimization to learn more.

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George Crump is founder of Storage Switzerland, an analyst firm focused on the virtualization and storage marketplaces. It provides strategic consulting and analysis to storage users, suppliers, and integrators. An industry veteran of more than 25 years, Crump has held engineering and sales positions at various IT industry manufacturers and integrators. Prior to Storage Switzerland, he was CTO at one of the nation's largest integrators.