What Is Storage Snapshot?

Imagine you're a giant, and you're walking through your house. You come across a closet that's packed full of boxes. You want to clear out some space in this closet but avoid taking the time to sift through each box individually. So instead, you grab all of them and toss them onto the lawn. That's what a storage snapshot does for data. It takes a "picture" of everything on your disk drive and writes it to another device, usually some tape or disk backup system, as one large chunk of information. If anything goes wrong with your original data, like a virus attack or hardware failure, you can rest easy knowing your data is safe and sound in its second location. A snapshot is a backup. It's a set of pointers to denote the data stored on a storage device, a disk drive, tape, or SAN. It can be considered a table of contents, with each pointer describing the information or data stored on the disk. The computer treats this snapshot as a complete backup of data. It's like a table of contents for your data. Imagine you're reading a book. Imagine you're in the middle of an excellent book, and you realize you want to reread some of what you've already read. Where do you go? What page are you on? How much have you read so far? You could guess what page of the book would contain the answer to all your questions, but it wouldn't be exact. It might be on page 6 or page 7. Once you found that page, how long would it take for the words to make sense again? A storage snapshot does for your data: it gives an exact picture of how things looked when the snapshot was taken, not just an approximate version of what they might look like now.