Archive, Backup, and Disaster RecoveryBacking up, archiving, and preparing for disaster recovery are obviously related. They overlap, but each one names a different purpose. Doing a good job at one of them doesn’t mean they’re all covered. Let’s consider what each one involves. Backup The purpose of a backup is to restore files that are lost or damaged. Recovery needs may range from a single file to an entire drive. A backup volume can be local or remote. It can be quick to access for getting back single files, or intended mostly for bulk recovery. Its focus isn’t long-term storage, though durability is a good quality. Versioned backups provide extra safety. A file can be corrupted, without being noticed, for a long time. If only the current version is backedup, and it’s corrupted too, that’s not useful. A backup that includes older versions gives a better chance of recovery. Many approaches are possible:
- An attached drive. Software does frequent incremental backups automatically. It’s convenient, and it’s always up to date. The disadvantage is that malware or physical damage to the computer might affect the backup drive as well.
- A shared storage system. Network attached storage (NAS) provides a large amount of backup space and keeps everyone’s backups together. It simplifies backup management if there are a large number of users.
- Tape backup. Tape is good for high-volume storage and allows saving multiple backups. It’s good for recovering crashed drives, but not very convenient for restoring single files.
- Offsite backup. Cloud storage is safer than any local backup from events that affect a whole office. It needs a fast enough Internet connection.
- Selection. Not every file needs to go into an archive. Figuring out which ones are needed can be a complicated task. It’s necessary to take business goals and regulatory requirements into account.
- Durability. Unlike a backup, an archive needs to be kept intact for a long time, usually years. It needs to have its own backup. Storage media will eventually go bad, and old file formats may become difficult to process, so it can require periodic migration to new media and storage formats.
- Identification. The information in an archive needs to make sense years after it’s created. It needs to be well-organized, and it has to include enough metadata to reconstruct its context and purpose.