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.