1. A method for applying data retention policies, comprising: receiving a request for applying a data retention policy (DRP) to a proxy object; in response to the request: providing, by a content object retention management controller, a master command to a master-side content object retention management layer, wherein the master command comprises a managed-entity object (MEO) identifier (ID) and the DRP, wherein the proxy object is associated with a MEO identified by the MEO ID; generating, by the master-side content object retention management layer, a slave command based on the master command; issuing, by the master-side content object retention management layer, the slave command to a slave-side content object retention management layer (SCORML) comprising a MEO retention manager and a content object (CO) retention manager; obtaining, by the MEO retention manager, the MEO using the MEO ID; applying the DRP to the MEO, wherein applying the DRP to the MEO comprises modifying at least a portion of the MEO; determining, by the MEO retention manager and using the MEO, at least one content object associated with the MEO; obtaining, by the CO retention manager, content object metadata for the at least one content object; applying the DRP to the content object metadata for the at least one content object, wherein applying the DRP to the content object metadata for the at least one content object comprises modifying at least a portion of the content object metadata; and issuing, by the CO retention manager, at least one instruction to a distributed file system to apply the DRP to the at least one content object stored in the distributed file system.