6. Building the Recovery Environment

Definitions

Data mirroring

A replicate server is placed at a remote location. Transaction data that is written to the primary server is also written to the remote server, either simultaneously or in batch mode.

Data back up

Data which has been written to the primary server is copied to a back up tape, usually once per day. The back up tape may be used to reload the server if a system failure causes the primary server to lose its data.

A back up server may also be installed to allow speedier restoration of service in the event of primary server failure.

Off site back up

For business contingency purposes, back up servers and tapes must be located away from the primary site, hence the term 'off site back up'.

The difference between 'back up' and 'off site back up'
In MSTA methodology, both of these terms have valid uses and they are quite different.

A back up tape, server, file etc. may be viewed as a replacement for a damaged item. In this context it is important that the back up is located close to the item which it is protecting, so that the back up file or device is readily available for use in the event of failure of the primary item.

Conversely, a business contingency back up tape, server, file etc. must be located in a secure environment, several kilometres from the primary item that it protects.

Because the off site back up is held remotely, its use for normal back up purposes is inconvenient. Consideration might, therefore, be given to the preparation of two back ups, one 'on site back up' and another 'off site back up'.

MSTA rule 2:

The number of recurrent procedures, introduced for purely business contingency purposes, should be as near to zero as possible, consistent with the provision of adequate BC protection.

Optical imaging

Electronic scanning and storage of document images as data files, which can be indexed and later retrieved, using data back up procedures.

Media Archive

Specially secured building, with closely controlled climatisation, where intrinsically valuable items, such as documents, data tapes and disks, may be stored, in comparative safety, remote from the company's offices.

Fire proof vault / safe / container
Specially constructed room or container where intrinsically valuable items, such as documents, data tapes and disks, may be stored, in comparative safety, within the company's offices.