What Is Data Deduplication?

You've probably heard of the "double-edged sword" before. It's a concept in many cultures and religions, including Christianity, Hinduism, and Islam. It's also referred to as "the sword of Damocles" since it was the sword that hung over the head of King Dionysius II—and was always threatening to fall on him at any moment. While having a sword hanging over your head might seem alarming, it could be good if you know how to use it. For instance, if you don't have enough room in your house for all your stuff, you could use data deduplication to store things twice—and then you'll have more storage space! Data deduplication is a magic trick that allows you to store your data twice. You might think this sounds like a bad idea—but it's not. Data deduplication works by keeping track of all of the files in your system, and if it finds any redundant copies of those files, it eliminates them from the system. So instead of storing all your files twice, you can keep them once and still have access to them whenever you need them! Data deduplication works by comparing incoming data to previously stored data. If it's already there, it's discarded. If it's new, the algorithm creates a reference. It's a lot like your relationship with your best friend: if you're having dinner together and he's got something to say about how you eat yogurt, he'll tell you what he thinks—but if he doesn't have anything new to say, he'll call you up and let you know how much fun he had at dinner. Unlike your best friend, this algorithm does not know if the new data is essential, so it just takes everything as gospel. This is why data deduplication can be dangerous: sometimes, files get deleted without anyone realizing they are necessary. That's because they were replaced by references to them instead of actual copies of the files themselves!