There are three main reasons organisations archive data:
- Records retention, for compliance and good corporate governance
- Long term retention, for preservation of information assets
- IT Optimisation
In reality, organisations archive for all these reasons but one will be the primary drive to initiate the archiving of information. Based on the reasons why organisations archive information, the fundamental requirements of archiving are:
- Lower cost than existing primary storage
Information stored in an archive should cost less than leaving it on the primary system. This should not only consider the acquisition cost of additional primary storage but also the disaster recovery procedures and the operational costs.
- Long term retention
Long term retention is generally agreed to mean longer than the reliably life time of the original system it is stored on. Hence, with a primary RAID system this is beyond 4-5 years. After this period to maintain access to the data the storage system would need to be replaced and the data migrated to this new system.
- Compliance with regulations
A detailed analysis of the thousands of regulations is beyond the scope but the essence of these regulations is to ensure that the original record can be reproduced without being altered. The ultimate test is to produce the record in a court of law, prove it has not been altered and be able to use it as evidence.
- Transparent access to archival information
However the archive is implemented, the end users demand constant access to their information and hence the archive must be transparent to the end user. That is they don’t have to look elsewhere for their data and it appears to remain where they put it. In fact IT departments often implement these transparent archives without the end user being aware of any changes.
- Offline management of very old information
As information gets older the likelihood of it being accessed reduces considerably hence it is not necessary to store this on primary RAID with instant access. Furthermore, as archives tend to be filled up sequentially with little modification, the oldest information was often written to the archive first. Once the organisation no longer needs direct access to this information, it can be off-lined from the archive to further reduce costs. Off-lined data can be retained outside of the archival system and can be restored if the data is required. This allows organisations to avoid making decisions about deleting information.