Modern Database Management: Chapter 11 Review Question 23

Question

Briefly describe four threats to high data availability and at least one measure that can be taken to counter each of these threats.

Answer

Organizations now expect high availability of data. The database administrators must ensure data availability. Software, hardware, and management techniques are used to achieve this. Even though many methods are used, there is always a threat to the high availability of data. The threats and their counterattacks are discussed below. The threats are:

• Hardware failure
• Loss or corruption of data
• Human error
• Maintenance downtime

Their details are as follows.

Hardware Failure

When a transaction under progress is disrupted by a system crash or some hardware component, failure in the system causes hardware failure. The hardware failure may be caused by power loss, loss of communication during the transaction, components such as database server, and hard drive failure.

Solution for the problem
Always a standby system should be available in an organization. During hardware failure, the transaction process should be replaced with the system. For example, if one server fails to handle the process, the workload should be transferred to other standby servers.

Loss or corruption of data

Loss of data occurs during the transmission failure in the communication link or some human error. Inaccurate data can cause the database to get corrupted.

Solution for the problem
The database management system should provide periodic data backup; it should be done with the latest database recovery facilities. Backup facilities produce a copy of data periodically, at least once per day.