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A Rose May Be A Rose But Dedupe Is Not Necessarily Dedupe

Today just about every vendor in the storage market has data deduplication as a feature in one or more of their products. While those of us that work with multiple deduplication products on a regular basis know there are big differences between the various technologies that vendors call data deduplication many users don’t know how to pick the deduplication solution that will best fit their needs.

The breath of the deduplication market was brought into focus for me by recent articles on that listed 96 companies that sold products with deduplication and 24 deduplication patents issued or applied for from Sept-Dec of last year . As I was absorbing the amount of patent activity in deduplication, Sepaton CTO Jeff Tofano and I had a chat discussing a list of 10 questions users should ask when considering a deduplication solution.

Some of the questions are, as we would expect, targeted to the large enterprise market Sepaton addresses, and to some extent targeted to Sepaton’s strengths, but they do address issues any potential dedupe customer should pay attention to. Rather than create a slide show of the questions to generate a lot of page views, I’ll add a little commentary to each.

1-What impact will deduplication have on backup performance – both now and over time?

Performance is a key consideration for any dedupe system, if you can’t make your backup window, it doesn’t really matter how much data reduction you get. Post process systems like Sepaton’s will deliver consistent backup performance over time, while some inline systems can get slower when they’re full, especially if they’re not given enough time to perform housekeeping between backup and restore jobs.

2-Will deduplication degrade restore performance?

Post-process vendors argue that since they store the last backup set in its native form, restores are as fast as possible, while inline systems must reassemble all restores from data blocks that are scattered across the deduplication repository. While some early systems were much slower at restoring data than at backing it up, the difference is getting smaller and HP claims their StoreOnce systems are just as fast at restores as backups.

Before you select a system based on claims of restore speed, you should check to see how often you run large restore jobs from backups that are more than a day or two old, and you should bring the system(s) you’re considering into your environment for a proof-of-concept before signing on the dotted line.

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