How and where you store digital information will affect its viability over time. Digital information needs to be managed so that it meets the Digital Continuity Principles. This helps to ensure that it remains authentic, reliable, discoverable, accessible, usable, protected and preserved for as long as needed.
Digital information required for long-term retention or identified as high risk or archival value records, need particular care.
Storing digital information
How can digital information be stored?There are a number of ways in which digital information can be stored, including:
- online, whether locally on an agency server, or by hosted storage through the internet, for example in cloud storage. Online storage is characterised by quick access to the information.
- in offline storage from which data can be quickly retrieved through a near-line storage system and brought online for access. The offline storage is typically a tape library or CD jukebox. This is known as 'near-online' or 'near-line' storage.
- on removable media such as magnetic tapes, CDs, DVDs, memory cards, flash drives (USB sticks). These 'offline' storage devices are not usually directly accessible.
In addition, vendors are increasingly offering a range of data storage services which may combine elements of online, near-line and/or offline storage.
When digital information includes high risk or archival value records, you need to ensure that the storage used will most effectively keep the information authentic, reliable, discoverable, accessible, usable, protected and preserved for as long as needed.
In particular, there are risks with using removable media. Not only is there a risk that the media itself may have a relatively short life or its existence be forgotten over time, but the resources required to ensure its continuing survival are considerable. Removable media are often overlooked when systems are upgraded and digital records migrated to new formats.
Records held in online storage devices are immediately accessible to users and more likely to be identified and included in changes to agency systems such as system wide migration processes. Regular integrity checks and back up of digital records are more easily undertaken.
What to consider when storing digital information
Conduct regular integrity checks
Integrity checks, for example using checksum, are important to ensure that there has been no inadvertent change, deterioration or data loss. This should be a routine part of testing your business continuity plan.
Store devices in appropriate conditions
When storing digital records over time, ensure that the storage devices and the facilities housing them can appropriately protect the records and make them accessible.
Digital storage devices are susceptible to dust and fluctuations in humidity, temperature and radiation, and it is important to ensure that stable environmental conditions are maintained.
Refresh storage devices
Computer hardware and digital storage media can become obsolete rapidly. Software changes may also require format conversion to ensure that information remains accessible. It is imperative to continuously monitor digital records and refresh them as needed.
Deterioration of digital storage devices does not become obvious until the point of data loss, by which time it can be too late to salvage records. A regular back-up strategy can mitigate this risk.
When storage devices are replaced or upgraded, check that records that need to be refreshed or migrated are all included. It is also an excellent opportunity to dispose of information that is due for disposal in accordance with a relevant records authority.
Considerations for outsourcing digital storage
Outsourcing storage of digital information can relieve pressure on storage capacity and ICT resources while reducing costs.
The National Archives' advice on Outsourcing Digital Storage, the Records Management Risk Assessment Template and the Checklist for Cloud computing and information management provide a helpful understanding of the potential risks and considerations associated with outsourcing storage of your agency's data.