CloudBerry Backup creates a version of the file on backup storage each time the file is modified. Using purging options you basically configure how many versions to keep. This helps you keep the number of versions to the necessary minimum and cut down on storage requirements.

To configure default Purging Options go the main menu Tools | Options and click on the Purging tab. The options are

1. Purge versions older than. It will delete all versions from the backup storage older than specified time interval that you configure

2. Keep number of version. This is absolute number of the most recent file version to keep.

CloudBerry Backup will always keep one version (the last version) of the file regardless of how purging options are configured. Furthermore, even if you delete a file on your computer it will still stay on your backup storage.
We will add an option that will delete file on online storage when you delete it locally in the future release.

Note: you can overwrite purging options when configuring Backup Plans

The other two options control the History which is used mostly for troubleshooting and doesn't add-up to storage requirements. You can look at the history records at the backup tab as shown on the screen below. In most of the cases you should leave default values. Again you can delete the records older then a give time interval or you can select how many records to keep.

Note, the history is stored on your local computer, not on the online storage and it doesn't consume much disk space. Anyways, don't worry too much about the History.

If you came to this post by chance you should know that CloudBerry Backup is a Windows program that leverages Amazon S3 storage. you can learn more about it at http://cloudberrydrive.com/