Storage Snapshot

Definition - What does Storage Snapshot mean?

A storage snapshot can be defined as a set of pointers to denote the data stored on a storage device. This storage device could be a disk drive, a tape or storage area network (SAN). It can be thought of as a table of contents with each pointer describing the information or data stored on the disk. This snapshot is treated by the computer as a complete backup of data.

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Techopedia explains Storage Snapshot

Just like a table of contents provides easy access to the contents in a book, a storage snapshot provides easy access to stored data and further speeds up the data recovery process.

A storage snapshot provides a concise look at how a file or device looked when the snapshot was taken. It is not the exact replica of data, rather just a quick picture of how data looked at that particular instant.

Storage snapshots can be classified into three types: copy-on-write snapshot, redirect-on-write and split-mirror snapshot:

Copy-on-write – Here data is copied into a pool of allocated storage. The major limitation of this method is that it impacts the performance of original data.
Redirect-on-write – It is somewhat similar to the copy-on-write. It offers efficient snapshots in terms of performance and space as it does not deal in double writing.
Split mirror – In this technique, a physical clone is created of the data which resides on a different storage space.