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How does a storage snapshot work with flat backup?

A flat backup may be cheaper than a traditional backup. It's based around use of a storage snapshot, which can provide nearly instantaneous recovery.

The concept of a flat backup is relatively simple, but the simplicity is also its appeal. Flat backups are based around the use of storage snapshots. A storage snapshot makes use of differencing disks as a way of rolling back a storage volume to an earlier point in time without having to perform a traditional backup or restoration. The main advantage provided by snapshots is nearly instantaneous recovery.

Traditionally, snapshots have not been regarded as a true backup alternative. They are more of a convenience feature than a backup replacement. There are a few different reasons for this, but the main reason is that a storage snapshot resides on the same storage array as the data that is being protected. Storage corruption or an array failure could wipe out both the primary storage and the storage snapshots. In other words, snapshots only provide the ability to do point–in-time recovery if the storage array remains functional.

Flat backups build on this concept by performing storage snapshot replication. The storage snapshots still reside on the same storage array they are protecting, but the flat backup replicates the snapshots to an alternate location. The snapshot replicas can be stored within the local data center or in a remote data center. As such, flat backups give you the ability to recover snapshots in the event of an array failure or array-level corruption.

Unlike a traditional backup, a flat backup does not require a backup server or a media server. This means that it may be far less expensive to produce a flat backup than to make traditional backups. One disadvantage, however, is that flat backups are not universally supported. Only a handful of storage vendors support flat backups.

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