Remove Configuration policies (Exchange policies) Start using retention storage policy.

Hi ​@Cyber_backup 

Good day!

Exchange Online and other Microsoft 365 workloads do not use the retention settings of the storage policy. Instead, retention is governed by the configuration policies (such as Office 365 Plans or Exchange Mailbox Plans), not by the storage policy retention. This is by design and cannot be changed for these workloads.

For Exchange Online backups in Commvault, retention is governed by the Exchange plan or Office 365 plan, not by the storage policy retention settings. 

Storage policy retention does not apply to Exchange Online or Office 365 agents.

This is by design:

The Exchange Mailbox Agent uses the retention rules that are defined in the Exchange retention policy. The agent does not use the retention rules that are defined in the storage policy.

Refer:
Create New Retention Policy (General)
https://documentation.commvault.com/2024e/commcell-console/create_new_retention_policy_general.html

Hello ​@Cyber_backup 

Adding details on the design consideration explain by ​@Syed_S, 

Why Storage Policy Retention Is Ignored

• Exchange Online, SharePoint, and OneDrive backups are considered "special clients" in Commvault. For these, the storage policy retention is not enforced. Instead, data aging is controlled by the application-level (Exchange/M365) plan retention settings.
• For Exchange, the retention is tied to the existence of the data in the source mailbox. A background process (true-up) checks for deleted items and only ages out data that no longer exists in the mailbox, according to the Exchange plan retention.
• Storage policy retention is job based and doesn’t provide granularity in handling retention.

Why Exchange Policy Retention Is Used

• The Exchange (or Microsoft 365) plan allows you to specify retention based on message received time or deletion status, which is more granular and aligns with compliance requirements for mailbox data.
• The retention logic is built to match how Microsoft 365 manages mailbox data, ensuring that backup and restore operations are consistent and reliable.

We would also prefer to go back to a traditional Agent, following traditional Storage Policy Retention. 

Given the number of mailboxes and our retention requirements, it becomes quite painful to manage.