Data recovery - Disaster recovery: Preparing for the worst

Generally speaking, the level of DR depends on the criticality of the data that is involved. For the most critical data, nothing other than continuous backup will do, with the result that all data operations, namely writes, deletes, copies and so on, are captured and recorded to a journal at all times.

The interesting feature about continuous backup is the fact that no data is actually moved around. This is because only the operations applied to the data are actually logged by the system.

For some situations, however, logging all the data operations may not be enough, as even a few minutes downtime whilst a system recovers is unacceptable. For these scenarios, the best option is a combination of synchronous and asynchronous replication.

This combination allows companies to perform synchronous replication of data between primary and secondary sites within a limited geographical area. The company can then further replicate the secondary sites on a timed basis to additional sites located much further away, using relatively low-cost asynchronous broadband connections.

Using this approach means that the company data is duplicated across two sites on the firm's existing intranet, with the data replicated to a third off-network site using a broadband connection.

Don't ignore the risk of data loss

Whilst Ontrack can offer assistance with critical data recovery, Alastair Molyneux says that companies of all sizes need to plan ahead. Our 20 years experience suggests that, however good the disaster recovery plan is, data loss is still likely to happen in an organisation. According to Molyneux, businesses need to be prepared for this eventuality.

Even a smaller-sized company would benefit from belonging to a programme, which would formalise the process to follow in such an event, For larger firms, the data recovery plan can be integrated to the disaster planning or even developed on a case-by-case basis.