by Joe Coffman

Created on: February 21, 2008

The enterprise database is the Holy Grail of Information Technology. All of the technological processes, all of the applications, all of the data entry, data analysis, ETL, business intelligence.it's all meaningless without a means to store and retrieve the data. Although there are many different brands of databases, they all have the same basic function of acting as an accessible repository of data.

It's no wonder that the Database Administrator (DBA) has such an important responsibility to act as the keeper and protector of the keys to the kingdom. It's also no wonder that the number one primary task of the DBA is to protect and preserve the database. Fundamental to that task is to insure that at least one up-to-date copy of an operational database is available at all times, and performing database backups is the most common method for accomplishing this task. An effective backup strategy is vital to any restore strategy, without which a database has virtually no purpose.

Most popular databases make use of transaction logs. A transaction log is a serial record of all the transactions that have been performed against the database since the transaction log was last backed up. Transaction logs backups allow you to recover the database to a specific point in time, or to the point of failure. Transaction log backups generally use fewer resources than database backups so you can create them more frequently, thereby decreasing the risk of losing data.

A typical backup strategy requires the DBA to make a database backup at periodic intervals, such as daily, and transaction log backups at shorter intervals, such as every 10 minutes. You must have at least one database backup or a covering set of file backups, to make transaction log backups useful. The interval between backups varies with the criticality of the data and the workload of the server. For security and performance considerations, it is recommended that transaction log backups be made on fault tolerant storage areas and on different storage areas than the actual database data.

One popular database management system (DBMS), Microsoft SQL Server, has features to make available several different recovery models to add flexibility to backups. Each recovery model addresses a different need for performance, disk and tape space and protection against loss. The different recovery models can be set and changed by the DBA at the database level.

Simple - This model permits high performance bulk copy operations & reclaims

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