The efficacy of a backup strategy can be determined by examining how well it conforms to the following rules. All backups should be:
Regular - at least once daily. More frequently if there is a lot of data changing
Automatic – human intervention should not be necessary for the backup to take place
Incremental - meaning that you can retrieve data as it was a given number of days or months ago
Redundant - at least two physically separate copies of the data to guard against one copy failing or being corrupted
Off-site - to mitigate fire and theft risks
Secure - data transmissions should be encrypted
Monitored – it is vital to know if there has been any problem with the backup process
Tested - can data be restored from the backup?
Backup Methods
Tapes, external or portable hard disks, CDs and DVDs have all been pitched as the solution to the backup problem, yet none of them satisfy all the rules listed above. It is true that such backup media can be stored off-site, but someone still has to remember to change tapes or insert CDs and then actually take them off-site. It is also questionable that it is appropriate for employees to take a copy of all the company data home. What happens when that person is on holiday or ill? Finally, how do you test each and every tape or CD - or do you take a chance that it will "probably be alright"?
The aim here is to ensure business continuity in case of data loss, but the methods outlined above seem unnecessarily complex and difficult to make foolproof.
Online Backups
Online backups are arguably the only backup methodology that satisfies all the rules. Open Source software makes it possible to run backups efficiently over an ordinary Internet connection by sending only data that has changed since the last backup. The data is sent over an encrypted connection which ensures data security. Backups can be run to two geographically disparate data centres, typically overnight, and the process can be fully automated. The status of the backups, including how old the most recent one is, can be monitored and support staff notified if there is a problem. Though there may be few changes to backup, it will even run on Christmas Day!
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