The Difference Between Versioning and Retention
By Cloud Direct • 26 Jul 2010
Versioning and retention are two terms that often cause confusion when talking about online backup. They both refer to the storage of data but their exact meaning often gets mixed up and misunderstood by many people. Hopefully this short post will clear some of the fog.
Versioning is a feature of online backup which allows a user to create multiple copies of their data from different points in time. It is the process of creating 'versions' of files - the exact state a particular file looked at a specific point in time. Online backup software provides this versioning capability because it allows users to 'roll back' and recover older versions of a file when needed.
For example, performing a backup on Monday will create version one. Performing a backup on Tuesday will create version two. Performing a backup on Wednesday will create version three, and so on.
However - and this is a key point - the backup software will only take a version backup of a file if it has changed since the last backup. In this instance, if you schedule a backup for Tuesday but no files have actually changed since Monday's backup then the software will not create a backup. This function is designed to save storage space - there is no point in creating two backups of exactly the same file.
The principle behind versioning is that it gives the user a choice of different file versions to restore from. In most cases, the last backup taken is normally the only one required - however, sometimes a user may need to go back a few more versions if a file error was not noticed for a number of days.
The number of versions/revisions kept by an online backup software varies. For example, Backup Direct's Connected software keeps, as a standard, ten previous file versions while our LiveVault software can keep as many as 170 previous file versions.
Retention refers to how long file versions are kept in storage for. For example, if an online backup service has 30 day retention, this means all file versions will remain in the data vaults for a maximum of 30 days each before being removed.
If a new backup has not been taken for over 30 days, the software will normally retain the last good backup indefinitely. This just means that there will be less previous file states to roll back to.
The two concepts can be slightly confusing but once you understand the fundamentals of them it is fairly straightforward. What we do ask people to do is to make sure they understand the software they are using before selecting data.
For more information on backup versioning and retention, please contact one of our solutions consultants on 0800 0789 437.
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