Professional SQL Server® 2005 Performance Tuning

15.1. Sizing

One of the most important steps in the database deployment life cycle is sizing. In order to accurately size a production environment it is important to take into consideration a variety of factors such as database size, number of transactions, number of users, and so on. Incorrectly sized production architecture often becomes the main reason for poor performance.

The SQL Server database world has become increasingly complex over the years. Today, multi-terabyte databases run alongside small to medium-size implementations. The variability in deployments is enormous and this leads to numerous hardware combinations possible. Thus, every deployment is different and there is no one-size-fits-all policy. Nevertheless, there are some common guidelines followed by most companies around the world when it comes to sizing their database architecture.

The process begins with the choice of a hardware vendor which for medium to large companies seldom differs from project to project. The next step involves answering a series of questions to determine the specific hardware requirements for the deployment. This process differs from application to application and is based on the criticality of the applications. However, below are some more common questions that every DBA needs to answer when correctly sizing a SQL Server database deployment:

• What editions of SQL Server will be deployed?

• How many SQL Server instances will be deployed?

• How many databases per instance?

• How many users per ...