When configuring a backup repository, you must specify the retention policy that would be applied during analyzing Office365 organizations' information before placing the actual organization data into the repository. This allows you to decrease the amount of data transferred over the network,
For example, if the retention policy is set to 3 years and you have configured a new backup job for this repository, this will work as follows:
- When you start a backup job, Veeam Backup for Microsoft Office 365 will first analyze the metadata of your organization. In particular, it will check the last item modification date and calculate the "age" of the item.
For example, if a backup job is about to be running at 10:00 AM on September, 15, 2017, and last modification was made at 10:00 AM on September, 1, 2014. This means that the item's "age" is 3 years and 2 weeks.
- The "age" is then compared with the value that is set in the Retention policy for mailbox items for repository (3 years in our example). If the "age" exceeds the specified interval, then such organization items will not be backed up into the repository.
In our example, an item is older than 3 years, so it will not be backed up. On the contrary; an item that was last modified at 11:55 AM on September 16, 2014, will be archived successfully.
This retention policy is then applied to the backup data on a target repository according to the following steps:
- After all suitable items are placed into the target repository, Veeam Backup for Microsoft Office 365 checks the retention policy application schedule. This setting defines how often Veeam should analyze the "age" of the data in the backup, comparing it with the specified threshold (a retention period), which is 3 years in our example.
- The retention period starting point is set to the current date/time. Obsolete data is removed from the repository automatically according to the following:
- An item will be removed from the repository if its "age" exceeds the threshold.
- The datastore will be removed from the repository when the last remaining items in the archive have their retention period expired and no data is arrived by that moment.
A retention policy is applied to the backup repository, not to the backup job. Therefore, if you want your data to be processed by different backup jobs and to be preserved for a different amount of time, you should target each of these jobs to a different repository, having its retention policies configured appropriately.