What is Backup Storage and the types of backup.

In computers, backup storage is storage that is intended as a copy of the storage that is actively in use so that, if the storage medium such as a HDD (Hard Disk) fails and data is lost on that medium, it can be recovered from the copy. In an enterprise, because the loss of business data can be a big problem differences, it is important that backup storage be provided.

On a personal computer, backup storage is commonly achieved with Zip drivers and DVDs or Store it in a local system itself. In an enterprise, backup storage can sometimes be achieved through replication of data in multidisc storage systems, such as RAID; as part of network-attached storage (NAS); as part of a storage area network SAN. Enterprise backup storage often makes use of both disk and tape as storage media. Special software is used to manage backup as part of a storage system.

Types of Backups:

1. Normal or Full Backup: A complete set of all files you wish to backup. This of this as your reference set. You only need perform a full backup occasionally. Pros and Cons for Full Backup:

Provides a complete copy of all your data, makes it easy to locate files which need restoring
Takes a long time and the most space on backup media, redundant backups created as most files remain static.

2. Incremental Backup: A backup of those files which have changed since the last backup of any type.

Pros and Cons for Full Backup:

Uses the lease time and space as only those files changed since the last backup are copied; lets you back up multiple versions of the same file.

Makes the job of restoring files fiddly, as you have to reinstall the last full backup first, then all subsequent incremental backups in the correct order; also makes it hard to locate a particular file in the backup set.

3. Differential backup: A backup of those files which have changes since the last full backup. Should be performed at regular intervals.

Pros and Cons for Full Backup:

Takes up less time and space than a full backup; provides for more efficient restoration than incremental backups.

Redundant information stored, because each backup stores much of the same information plus the latest information added or created since the last full backup. Subsequent differential backups take longer and longer as more files are changed.