Backup and Recovery

Backup and Recovery

1. Backup Strategies

   • Should ask: What Data? How Often? When? Backup Media? Where will it be stored?
     •  What Data, How Often, When, Backup Media, Where will it be stored.
     • What Data: the amount of data may affect the type of backup required.
       • Full Backup: backing up every file or folder on a system. Ensures everything is saved, but may take some time depending on the size of the backup.
       • Differential Backup: Only backs up DATA that are different/has been changed since the last FULL backup.
       • Incremental Backup: Backs up FILES that have been changed since the last backup regardless of type of backup.
     • How Often: the frequency of backup.
       • This depends on: how often the data changes and How much an organisation is prepared to loose.
         • RAID: Redundant Array of Independent Disks
           • Backs up data as soon as it changes through "mirroring", ensures continuity of service should a drive corrupt/fail.
     • When: at what point should data be backed up?
       • Many systems back data files up overnight when no data files are in use. sometimes this is in addition to mirrored (RAID) servers.
       • Programs and software may only change every so often, and so may only be backed up when an update occurs.
       • For individual personal computers, a weekly update may be enough.
     • Backup Media: What should the backup be stored on?
       • Magnetic Tape: most common medium, used to store large quantities of data and for archiving historical data. The main choice for organisations
       • Hard Disk: More affordable than Magnetic Tape, and so may be favorable for individuals and small businesses.
       • Optical Disk: Most common type is a Recordable CD. Small capacity (up to 700MB) meaning only suitable for home/individual use. Cheapest method, however has large amount of drawbacks.
     • Where Will it be stored?
       • Backed up data should be stored away from the main server. As in the event of a disaster (i.e. flood, fire, etc) having the main and the backup servers in the same room may mean all data is lost.
       • Cloud Storage is always a good option IN ADDITION to a physical server. An organisation must ensure that the cloud storage complies with the DPA

2. Recovery Plan

   • Should ask: Who is responsible? Where is it stored? and the need for continuity of service.
     • Who is responsible?
       • As an individual, you are responsible for ensuring a recovery plan is in place by performing regular backups on media devises away from the main system. As an organisation, there may be one person, who is responsible for scheduling backups and performing recovery tasks when required.
     • Where is it stored? (and how quickly can it be accessed?)
       • Different types of backup will take different amounts of time to restore this should be considered within a recovery plan. (e.g. a full backup is quicker to restore than a incremental backup.)
     • The need for continuity of service
       • A high need for continuity of service means that there can be no downtime. This means that the server should have a UPS (Uninterruptible Power Unit) to allow up to an hour for server managers/technicians to fix the problem.
       • To achieve Continuity of service, a set recovery plan is needed to ensure the server is returned to normal operating level as soon as possible.