Informix database server database spaces

The Rational® Synergy database uses the Informix® server to store its metadata. The terms database server, online server, Informix server, online Dynamic Server, and Informix server are used interchangeably in this Information center.

An Informix server consists of four dbspaces: rootdbs, log, tempdbs, and ccm. Each dbspace serves a specific purpose and requires a minimum of one chunk file. (A chunk file is a physical disk space.) At least four chunk files are required for a server.

A Rational Synergy database consists of a file system data and Informix metadata database spaces (dbspaces). The file system portion uses standard UNIX® file systems to store control information and the sources of files under CM control. The Informix portion, which holds metadata such as the owner and status of objects, is stored in databases spaces (dbspaces) on the Informix database server.

rootdbs

Informix servers use the rootdbs dbspace to store system data, physical logs, initial logical logs, and temporary data. It requires a chunk file, ROOTPATH, to store its data. The ROOTPATH and the size of it is specified by the user when an Informix server is created

log

The log dbspace is used to store logical logs that the Informix servers use to store database changes. The log dbspace requires a chunk file that the user specifies during the server creation. The size is 1 MB per user. You can override the calculated size by specifying a size larger than the default when prompted by the server creation program.

tempdbs

The tempdbs dbspace is used to store temporary tables and sort files. Some queries create and access large temporary files. Therefore, placement of temporary dbspace is a critical performance factor. You specify the temp path and size when you create the Informix database server.

ccm

The ccm dbspace is used to store data for Rational Synergy databases. Initially, this dbspace uses a single chunk file. You specify the ccm path and size when you create the Informix database server.

The default space suggested for the root, temp, and log dbspaces is about 1 MB per user. For the ccm dbspace, it is about 2 MB per user. For the default 20 users, the total dbspace is about 100 MB.

For more information about chunk files, see Dbspace chunk files.


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