HSM debate rages: Cost versus user ease
Compared to just five years ago, it's amazing how much more storage modern applications and their data require. According to InfoWorld's research, maintaining adequate capacity is the top storage-related concern of IT leaders. The typical company will expand by 50 percent in the next year. What will you do with all that data?
Most IT operations work on a two-tier storage scheme. Tier one, online storage, includes files that reside on hard disk and are immediately accessible. When those files are backed up to magnetic tape, they reside in tier two, offline storage. Files not needed for day-to-day operation are often deleted from online storage after they've been backed up.
A hierarchical storage strategy retains the online and offline levels but inserts a third tier between them. This tier moves rarely used files from hard drives to more cost-effective archival media. It does not expand capacity directly, but it can help IT planners make smarter use of expensive disk storage. HSM (hierarchical storage management) software is required to make three-tier strategies work.
Despite its benefits, HSM is not without controversy. Its success depends on making it easy for users to request the restoration of archived files. But conservative shops balk at placing so much power in users' hands, instead enforcing a use-it-or-lose-it approach.
Tom: I am staunchly in favor of hierarchical storage strategies, and I believe HSM should be in place in almost every enterprise even though it is not widely deployed in corporate IT; most companies still use two-tier schemes that put archived files effectively out of reach.
Resistance to HSM stems from two primary causes. First, the purpose of HSM is misunderstood. When HSM is considered, it is often voted down for failing to deliver benefits, such as saving money on disks, that it wasn't designed to provide. The second reason is cultural. Corporate IT departments are accustomed to setting and executing enterprise storage policies. HSM shifts some of that power to users, who place automated file-retrieval requests that the HSM system fills with little intervention from IT.
Jim: Tom, you're always giddy over burgeoning comfort technologies, but I need to hear HSM justified from a business standpoint before I can feel comfortable making an across-the-board purchasing recommendation.
The number of companies that actually require on-demand access is limited. Tom, you need to weigh the budgetary impact of availability and unmanaged capacity against user quotas and the complexity of HSM.
True, HSM can deliver benefits such as capacity on demand. True, it definitely offers a leg up over manual capacity management measures. But it doesn't offer any measurable cost savings or a clear-cut ROI. HSM is a huge indulgence.
Should a successful storage management strategy offer unbridled capacity? If you build it, they will come. And they'll fill it with personal files, multimedia, and MP3s. User abuse of network storage often sits at the root of spontaneous consumption problems; now you're suggesting that we put these users in charge of managing their own storage?
Sorry, Tom, but when weighing costs against the comfort benefits of HSM, most IT departments
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