1. A data processing system (DPS) operating within a distributed storage system (DSS), the DPS comprising: at least one processor; a memory system having stored therein a utility, which when executed by the processor causes the processor to: identify a pre-established data storage threshold value for an amount of data that can be stored within the DSS; track a current storage usage for an amount of data stored within the DSS; determine whether the current storage usage exceeds the pre-established data storage threshold value; in response to determining that the current storage usage exceeds the pre-established data storage threshold value, calculate a target number of documents that can be deleted from the DSS based on an amount by which the current storage usage exceeds the pre-established data storage threshold value, wherein the current storage usage is proportional to a number of stored documents in the DSS, wherein said stored documents have a same document type; assign stored documents to a plurality of groups including a set of document categories based on corresponding data characteristics, wherein said groups are ordered based on a relative index associated with corresponding values for data characteristics, wherein all of the stored documents assigned to at least one of the plurality of groups can be deleted, based on an order associated with the relative index of the document categories, in order to provide the target number of documents that can be deleted; and delete all of the stored documents assigned to at least one of the plurality of groups in order to remove the target number of stored documents.