Currently, most storage providers use this technology called Snapshot. This technology uses a method called “Copy On Write” which means that, if a location is changed, old data from the time snapshot for that location is stored in a repository called SnapSpace. The consequential snapshot will look like an actual volume, containing data at the time of snapshot taken.
Snapshot is also called Shadow Copy in windows Terminology. But the difference between windows based shadow copy and storage based snapshots are that windows based shadow copy will take the CPU cycles of the server, but storage snapshot does not.
Why do I need it?
Below listed are some usages of Snapshot.
– Backup: Take a snapshot, backup the snapshot.
– File Recovery: In case a file is deleted accidentally, it can be retrieved by going back to the snapshot.
– Take a snapshot, give that to one or more other groups to work on it, while live volume is changing.
For more details on StoneFly’s Snapshot, Visit StoneFly’s iscsi.com
Also refer the link given below: