Table of Contents

Overview

The Digital Repository Service (DRS) is the Harvard Library’s centrally-supported programmatic solution for long-term preservation of the University’s digital resources. For purposes of effective and affordable curatorial and operational management, the DRS supports dynamic disposition of all managed digital files to various storage locations according to the storage classification, as designated by a curator.

One of the primary preservation strategies of the DRS is reliance upon geographically-dispersed storage replication across heterogenous storage media to minimize opportunities for single points of failure.  Files are dispositioned across different storage locations according to a policy designed to ensure that at least one full copy of all managed files is in online, on-premises storage and another one on off-site tape. Additional replicas and locations provide added-value preservation assurance.

Storage classes

The DRS supports six (6) distinct DRS storage classes: Sensitive, Repurposable, Deliverable, Data, Basic, Large, and Archival. The central concept of the new infrastructure is that content should be hosted on storage platforms that best match their curatorial designation (see the Table below). Upon deposit of content into the DRS, files will be automatically assigned a storage class based on file roles and deliverable logic, but curators can also manually designate the appropriate storage class for the content. Please visit the LTS wiki documentation for more information on Assigning Storage Classes and Editing Metadata and Storage Classes. The Digital Preservation Services team is available for consultation on the selection of storage classes.

Many classifications can be mapped from long-standing content characteristics and DRS metadata.  For example, sensitive data contributed to the DRS from the EAS (Email Archiving System) would naturally be assigned to the Sensitive class.  Large files can be assigned to the Large class based on their size.  Deliverable material, i.e., that having Public (P) or Restricted (R) access and an associated delivery service URN, would be assigned to the Deliverable class.

Note, however, that any files necessary for delivery service function (IDS, PDS, SDS) must be assigned to either the Deliverable (DE) or Repurposable (RE) classes in order to be visible to the services.  This includes primary files, e.g., streamable audio and video, PDS objects, as well as ancillary files, e.g., audio playlists, video closed captioning, individual PDS page images, etc.

Storage cost calculator

Use this storage calculator to estimate storage costs in the DRS. For each storage class, enter the size of the deposit in gigabytes (GB). You can additionally select the number of years over which you would like to project costs. The calculator will summarize total costs as well as the quarterly fiscal year (FY) charge.