Siebel Deployment Planning Guide > Data Integrity and Capacity Planning >

Sizing the Database for a Siebel Deployment

As with most client-server applications, the overall performance of Siebel Business Applications is largely dependent on the I/O performance of the database server. To promote optimal I/O performance, you must arrange the tables and indexes in the database across available disk devices in a way that evenly distributes the I/O load.

The mechanism for distributing database objects varies by RDBMS, depending on the way storage space is allocated. Most databases can force a given object to be created on a specific disk.

To verify which RDBMS products, versions, and patch levels are supported, see Siebel System Requirements and Supported Platforms on Oracle Technology Network.

In your planning, you need to allocate space for multiple purposes, including system storage space, undo or rollback space, temporary table space, and space for logs and system files, as well as space for Siebel data and indexes. If you allocate too little space for your system, you reduce performance; if you allocate too much, you waste disk space.

The space the RDBMS needs varies primarily based on the total number and types of users supported, as well as the transaction mix and rate. Consult the RDBMS vendor's documentation for more information on these requirements.

The space required for Siebel data and indexes varies depending on what Siebel Business Applications functionality you will implement and the amount and nature of data supporting that functionality.

NOTE:  The Siebel Servers in a Siebel Enterprise Server can connect to only one database. For example, you cannot configure both an Oracle and an IBM DB2 database for use by the same Siebel Enterprise Server.

To determine the size of the database required for a Siebel deployment

1. Determine the total number and types of users of Siebel Business Applications (for example, 500 sales representatives and 75 sales managers).
2. Determine the Siebel Business Applications functionality that you will implement and the entities required to support them. Usually, the largest entities are as follows:
   • Accounts
   • Activities
   • Contacts
   • Forecasts
   • Opportunities
   • Service requests
3. Estimate the average number of entities for each user (for example, 100 accounts for each sales representative) and calculate an estimated total number of records for each entity for your total user base.
4. Using standard sizing procedures for your specific database, calculate the average record size for each entity and multiply by the total number of records.

   Typically, these entities span multiple physical tables, all of which you must include in the row size calculation in order to determine the estimated data size for the largest entities.

5. Add additional space for the storage of other Siebel data. A rough guideline for this additional amount would be half the storage required for these key entities.
   • Indexes typically require approximately the same amount of space as data.
   • Factor growth rates into your total size calculation.
   • Factor a margin of error into your total size calculation.