Disaster Recovery plan: Disaster recovery plan is also called as business continuity plan or business process continuity plan.
DRP: DRP stands for Disaster Recovery Planning should include information security, asset security, and financial security plans.
As part of disaster recovery, it is important to have a location from which the recovery of a failed site can take place. This location is known as a backup site. In the event of a disaster, your site is recreated at the specified backup site and made available. Once the failed site is recovered, the backup site will be reverted to its previous status.
There are three different types of backup sites:
1. Cold backup sites
2. Warm backup sites
3. Hot backup sites
1. Cold site: Here the bare minimums, such as space and furniture are available. Everything else need to be procured. The delay going to a fully operational site could be very large in this case
2. Warm site: Here, most of the hardware is in place, and probably you need to recover the site from off-site backup, and configure. The site could be restored in a reasonable amount of time.
3. Hot site: A facility designed to provide immediate availability in the event of a system or network failure. All the systems are appropriately configured and working. Only thing that is required is the restoration of latest backup.
Note that onsite backup is not a back up site.
Backup concepts: It is recommended to store the backup tapes in a secure, physically distant location. This would take care of unforeseen disasters like natural disasters, fire, or theft. It is also important that the backup tapes are regularly verified for proper recovery in a test server, even though recovery is not really required at that time. Otherwise, it may so happen that you find a backup tape corrupt when it is really required. The backup policy identifies the methods used to archive electronic and paper file systems. This policy works in conjunction with the information retention and storage policies.
A properly managed tape backups should include the following:
There are primarily three types of backups:
1. Full backup: Here all the data gets backed up. It usually involves huge amounts of data for large systems, and may take hours to complete. A full backup is preferred instead of incremental or differential backups where it is feasible. However, when there is large amount of data, full backup is done once in a while and incremental or differential backups are done in between. A backup plan is usually put in place prior to taking backup of data.
2. Differential backup: A differential backup includes all the data that has changed since last full backup. The "differential backup" that was taken earlier (after the "full backup" but before the current "differential backup") becomes redundant. This is because all changed data since last "full backup" gets backed up again.
3. Incremental backup: It includes all the data changed since last incremental backup. Note that for data restoration the full backup and all incremental backup tapes since last full backup are required. The archive bit is set after each incremental backup. Incremental backup is useful for backing up large amounts of data, as it backs up only the changes files since previous incremental backup.