The Office 365 (O365) Backup database does not follow the normal Veeam advanced retention scheme. Normally, Veeam will enforce retention by removing backup images that were created before the earliest date in the retention period. Instead, retention is based on each item’s last-modified date.
How is O365 Backup Retention Enforced?
Each time the retention policy is processed (daily on each Green Cloud repository), the Veeam O365 Backup server will first check the retention policy against the current date and time to determine the earliest last-modified date that will be allowed on items in the repository. Then, during processing, each item’s last-modified date is checked, and items modified earlier than the retention period are removed. For example: under a retention policy of two years, a file that was last modified at 9:30am on September 2, 2017 will be removed during a retention check that runs at 1pm on September 2, 2019.
Does It Matter When the Item Was Added to the Backup?
No, it does not. Only the last-modified date matters with respect to retention.
Can I Change My Retention Period?
Yes, you can. Retention periods are set in the Green Cloud Portal (https://portal.greenclouddefense.com). Green Cloud supports the following retention policies: 1 year, 3 years, 5 years, 7 years, and Forever.