Digital records, storage media and systems
Select storage for digital records
When looking at storage for digital records, you need to think about the mode of storage, the technologies or media you store them on, and where the media itself is stored.
Choose digital storage based on:
- how often you need to access the records
- access restrictions for the records
- the file format
- how long you need to keep them
- the best way to preserve and manage the records
- what options are available.
Most digital storage devices have a limited life expectancy of around 5 to 7 years.
- the specific combinations of hardware and software needed to access the information
- moving records across to new media before the storage devices or related equipment become unsupported or obsolete
- the media you choose and how long you will be able to use it
- security or access restrictions that may rely on the specific format or storage media.
Consult with your IT area or specialist about storage media and file formats.
See also portable storage devices and information privacy.
Modes of digital storage
There are 4 main ways to store digital records:
Note: There are additional recordkeeping considerations when using cloud-based storage and services.
Types of storage media
Storage media is usually either:
- Solid state media–data is stored in 'flash memory' rather than rotating disks or optical media (e.g. USB flash drive or thumb drive, SD and CF cards used in cameras). Some newer portable hard drives and external storage devices are solid state media.
- Magnetic media–information is recorded and retrieved in the form of a magnetic signal (e.g. floppy disks, magnetic hard disks, magnetic tape, including reels, cassettes and cartridges)
- Optical media–information is read optically (by a laser) (e.g. CDs, DVDs). These may be one use only or reusable. Rewritable optical discs–also known as EO (erasable optical) disks–allow the user to record information on a disc, erase it, and replace it with new data. The most common forms of rewritable discs are CD-RW and DVD-RW.
Criteria for storage media
Assess storage media using these criteria:
Availability and speed
If records need to be accessed often or quickly, choose a storage mode with a fast retrieval time.
The longevity or lifespan of media depends on the type, format, quality of manufacture, frequency of handling and proper storage conditions.
The lifespan of the media should be proven and appropriate for the records. Longer lifespans will reduce the need to migrate records, refresh the media or carry out other preservation activities.
Most media will only last 5 to 7 years. Even if storage media is capable of lasting longer under appropriate storage conditions, the hardware or software required to access the information may become obsolete.
The selected media should be robust with a clearly defined migration path and widespread industry support.
Think about your current and future needs when considering capacity.
Robust error detection and integrity checks (e.g. checksums) should be used to ensure there has been no inadvertent change, deterioration or data loss.
Make sure that the media and/or the technology or hardware required to read the media isn't likely to become obsolete or unsupported in the near future.
Some older optical media and magnetic hard disks, tapes, cartridges and proprietary flexible disks (e.g. Bernoulli, Zip or Jaz disks) are at risk of obsolescence if they are dependent on specific operational environments or hardware.
The cost of storage should include the:
- capacity of storage media (e.g. storage space per gigabyte)
- hardware and software required to access the media or read the information
- special storage environments
- resources required for active management, monitoring, integrity checking and support.
You should consider the published failure rate or mean time to failure (if known) of the hardware.
The susceptibility of media to damage depends on the type, format, quality of manufacture, handling and treatment, and proper storage conditions.
You should implement controls to protect the media from damage during handling and usage.
Solid state media
Solid state storage devices are generally quite robust, but can be vulnerable to power variations, physical shock and high temperatures and humidity.
Magnetic and optical media
Find out more about magnetic and optical media for storing digital records.
Refresh digital storage media
You will need to maintain, refresh and update digital storage media every 5 to 7 years to ensure records remain accessible. Monitor this in a media refresh (migration) plan.
It is important that you carry out regular checks for deterioration. Media may need to be refreshed sooner if there are signs of deterioration.
Preserve digital records
Digital records depend upon software, hardware and media that change. Technological obsolescence and poor information management practices across the lifecycle of digital information place records at risk of losing their integrity and authenticity, or simply becoming lost or inaccessible.
Detailed metadata are critical for preserving digital records, documenting preservation activities and integrity checks.
If digital records are stored off-site, check what digital preservation activities the service provider does. Some storage facilities may only manage and monitor the hardware and media, not the data.
Options to preserve digital records
Migration and emulation are 2 options for preserving your records.
Continuing to manage the records in the original system or printing them are last resorts.
Migration is one of the most commonly used approaches for preserving digital records and is a means of refreshing storage media.
The main types of migration are system migration, version migration, and format migration.
Migrating records may be necessary if you are decommissioning or replacing a business system. You may also need to consider migration when reviewing business and recordkeeping applications.
There are risks involved in migrating records. Careful planning will help reduce risks and ensure that records are authentic and accessible in the new system. Find out more about migrating digital records
Emulation involves using current technologies to recreate an operating environment and software performance so that records can be kept in their original format.
This is only possible with specialised knowledge of aging technologies.
Actively manage the records in the original business system
This is an option if you have records that only need to be kept for a short time, or if migrating the records would affect their integrity, accessibility or usability.
There are a number of risks with this option, and you will need to conduct a thorough risk assessment. Consider:
- recordkeeping obligations
- retention periods
- other options
- whether records can be migrated successfully
- knowledge of the original system
- technological obsolescence
- lack of or reduced support for the system
- system maintenance
Using the original system is not recommended for records that need to be kept medium to long-term. If no other solutions are suitable, this may be an option until you find an alternative solution.
There are 2 options for actively managing the records in the original business system:
- Virtualise the business system
Maintain the business system as a virtual machine until the records can be legally disposed of. Virtualisation can allow you to run multiple systems on a single physical server.
- Retain the system on the original software and hardware platform
Use this option if the records cannot be migrated or exported immediately or easily, or the system cannot be virtualised.
Born-digital records should be kept digital. Printing records is not recommended unless all other options have been exhausted.
If you have to print the records, make sure that:
- all records and associated metadata are printed in a meaningful form
- you capture and manage the printed records in your agency's recordkeeping system
Digital continuity strategy
To make sure digital records are preserved, you should have a digital continuity strategy or plan.
The digital continuity plan should include regularly refreshing the storage media. It is not enough to keep records in their original systems or in off-line digital storage media.
Also consider the:
- different file formats your agency uses
- lifespan and vulnerabilities of storage media
- risks to records from digital rights management and encryption, particularly for long-term or permanent value records.
The file format you choose will affect how records are preserved and managed. The choice of format becomes more critical the longer a record has to be kept.
Find out more about which file formats to use.
Disposal of media and devices
Before an entire device can be disposed of, you need to check that all records have been captured and that any remaining information on the device has been destroyed.
Find out how to dispose of media and devices.