Differences between backup and archive

Akkamon Srihiran is global services manager at EMC Information Systems (Thailand).

The amount of data that needs to be protected is therefore overwhelming and ultimately, this point alone should be sufficiently compelling for organisations to consider backup, recovery and archive strategies.

Although backup was an IT mainstay in the past, it requires the introduction of other technologies as data volumes increase, to assist in the management of data to be backed up so that backup windows and timeframes can be met.

An archive is a collection of historical records, and also refers to the location in which these records are kept or maintained. "Archives" are made up of primary source documents which have been accumulated over the course of an individual or organisation's lifetime. For example, the archives of an organisation tend to contain different types of records such as administrative files, business records, memos, official correspondence and meeting minutes.

In archiving, there's an application that creates the logical link between the location of the electronic record (doc, xls, pdf, etc), called the "source", and the repository (CAS, NAS, ATA disk, etc) where the record ends up being a stored, called the "target". The logical link to the original data is often referred to as a "file stub".

It is important to note that unlike backup, which often ends up with multiple copies of the same data, archive has only a logical link to the original data. There are no other copies of the original data unless the data is replicated elsewhere. If data is not replicated, it is strongly recommended that archive data be backed up regularly.

This brings up some interesting points when discussing backup and archive.

Historically, both these concepts have been viewed as totally separate activities, often managed by different groups within an organisation. However, removing the separation between backup and archive and combining the two brings about advantages to both processes.

Archive allows for data that isn't being accessed regularly to be removed from high-cost primary storage, which reduces the amount of data that needs to be backed up, thus significantly reducing the time taken.

Backup protects all the production and archive data in case of a data loss. However, when the archive data is replicated, the requirement for backing up the archive also diminishes. The main benefit of backup is that it allows for archive applications such as configurations, settings, policies and associated databases to be protected. This allows for prompt recoveries, enabling end-users to access their data as required.

Akkamon Srihiran is global services manager at EMC Information Systems (Thailand).