CTDA Membership Cost Schedule

May 6, 2024

Download a PDF of this page

Participation in the CTDA is FREE to all members with certain limits. This document explains when and how members are asked to pay for additional storage beyond their initial storage allotment.

Background and Justification

The CTDA developed out of UConn’s need to build its own digital preservation infrastructure and its mission to support educating Connecticut’s citizens. Infrastructure is shared with other Connecticut-based members with the explicit understanding that the CTDA exists as a program of, by, and for the UConn Library. Policy documents explain the relationship and responsibilities agreed to by members who use the system and by the UConn Library who supports and maintains the system. 

Infrastructure is shared equally among all members of the CTDA. While most CTDA members have relatively few records in the system (numbering in the thousands), some members have hundreds of thousands of records in the system, and at least one has more records in the system than UConn itself.  

More content in the system means more of a share of the system load for that member. This means some members consume a much larger amount of system resources (storage, computing power, customer support, etc.) than others. While UConn is willing to subsidize the cost of preservation for a reasonable number of objects, members with exceedingly large numbers of objects begin to impact the total cost of preservation itself. This cost schedule was developed to recover these unexpected costs to the system. 

Total Cost of Preservation (TCP)

The concept of total cost of preservation was developed at the California Digital Library (CDL) in the early 2010s. CDL did extensive research and analysis of technical, administrative, and other costs related to digital preservation and the CDL public systems and developed TCP expressed in cost of preservation per TB per year and POSF (Pay Once Store Forever).  

The CTDA uses a similar model to determine the TCP at UConn. We take the total direct costs to the UConn Library to run the system (e.g. salaries, wages, benefits, direct costs of software purchases, and vendor costs) combined with UConn’s  “Other Sponsored Activities” indirect cost rate from: Facilities and Administrative (F&A) Costs . TCP is calculated yearly based on direct and indirect costs divided by the total size of the system. 
 Find out how TCP was calculated this year

Cost Schedule for FY 24/25

(Effective, July 1, 2024)

As mentioned above, total cost of preservation is not based on number of objects in the system, but the total volume of those objects. This most accurately represents the true cost of preservation since preservation activities are undertaken on bits and bytes rather than files, and customer support increases with the size of the collection in the CTDA. To maintain equity among the members and to not overburden the UConn Library with costs beyond what would be customary and expected in running a preservation repository system for itself, the CTDA has developed this Cost Schedule:

• The cost schedule sets the price per TB charged to member institutions on a POSF (Pay Once Store Forever) basis
• Every member gets a one-time 1 TB allocation without charge, additional storage can be purchased in 1 TB units at any time.
• The cost schedule is calculated and announced to members in January, for implementation the following July.
• The difference between the TCP and the subsidized rate can be used as cost share in grant applications. 
• A "year" is defined as July 1 to the next June 30.

For a more detailed example of how the Storage Fee Schedule is derived, see Calculating The Total Cost of Preservation.

Cost Schedule Example

Member A were awarded a grant to digitize a selection of their holdings eventually comprising 10TB of digital files over the next 2 years. With funding from their granting agency, they decide that rather than purchasing 5TB each year, they will take advantage of the volume discount and purchase all 10TB in the same year.

Although they have approximately 300GB left from their free one-time initial allocation, additional storage must be purchased in 1TB units so they will purchase 10 TBs to accommodate their new content. The invoice would look like this:  

What Paying for Storage Really Means in the CTDA

The cost of CTDA services is expressed in dollars per Terabyte of “storage.” However, there is more to storage in a digital preservation system than just disk space. When you purchase “storage” from the CTDA you are purchasing a system of digital preservation and access activities based on international standards designed to ensure the permanence, integrity, and accessibility of your digital content. 

Digital preservation activities rest on several principles that underpin digital preservation and make it different from backup and disaster recovery. These principles have developed over the past 30 years and most recently have been expressed as FAIR principles:

• Findable—permanent globally unique internet address

• Accessible—documented way to interact with the content and metadata

• Interoperable—content and metadata can be seamlessly used in other applications and dissemination

• Reuseable—metadata and content can be used in ways not intended by the original creator

A digital repository based on these general standards must meet many more requirements before it can be considered “trustworthy” in the digital preservation sense. These requirements are set by international certification organizations. The CTDA measures itself against the requirements of Core Trust Seal (CTS).  Core Trust Seal requirements are spread across sixteen different areas of organization, management, and technology. The CTDA meets the requirements in each of the 16 CTS areas of evaluation. 

Core Trust Seal Requirements for Trustworthy Digital Repositories

Organizational Infrastructure

• Mission & Scope (R01)
  • The repository has an explicit mission of preservation and access

• Rights Management (R02)
  • The repository maintains all applicable rights and monitors compliance.

• Continuity of Service (R03)
  • The repository ensures ongoing access to and preservation of its data and metadata.

• Legal & Ethical (R04)
  • The repository ensures to the extent possible that data and metadata are created, curated, preserved, accessed and used in compliance with legal and ethical norms.

• Governance & Resources (R05)
  • The repository has adequate funding and sufficient staff managed through a clear system of governance to effectively carry out the mission

• Expertise & Guidance (R06)
  • The repository adopts mechanisms to secure ongoing expertise, guidance and feedback-either in-house, or external.

Digital Object Management

• Provenance and authenticity (R07)
  • The repository guarantees the authenticity of the digital objects and provides provenance information.

• Deposit & Appraisal (R08)
  • The repository has defined submission criteria.

• Preservation plan (R09)
  • The repository manages digital preservation in a planned and documented way.

• Quality Assurance (R10)
  • The repository addresses technical quality and standards compliance, and ensures that sufficient information is available for end users to make quality related evaluations. (Levels of Curation)

• Workflows (R11)
  • Digital object management takes place according to defined workflows from deposit to access.

• Discovery and Identification (R12)
  • The repository enables users to discover and refer to content in a persistent way.

• Reuse (R13)
  • The repository enables reuse of the digital objects over time.

Information Technology & Security 

• Storage & Integrity (R14)
  • The repository applies documented processes to ensure storage and integrity. 

• Technical Infrastructure (R15)
  • The repository is managed on well-supported operating systems and other core infrastructural software and hardware.

• Security (R16)
  • The repository protects the facility and its data, metadata, products, services, and users.