# Changing the system-wide properties by using the derby.properties file

You can set persistent system-wide properties in a text file called derby.properties, which must be placed in the directory specified by the derby.system.home property. There should be one derby.properties file per system, not per database. The file must be created in the system directory. In a client/server environment, that directory is on the server. (For more information about a Derby system and the system directory, see "Derby System" in the Derby Developer's Guide.)

Derby does not:

- Provide this file
- Automatically create this file for you
- Automatically write any properties or values to this file

Instead, you must create, write, and edit this file yourself.

The file should be in the format created by the java.util.Properties.save method.

The following is the text of a sample properties file:

    derby.infolog.append=true
    derby.storage.pageSize=8192
    derby.storage.pageReservedSpace=60

Properties set this way are persistent for the system until changed, until the file is removed from the system, or until the system is booted in some other directory (in which case Derby would be looking for derby.properties in that new directory). If a database is removed from a system, system-wide properties do not "travel" with the database unless explicitly set again.

Parent topic: System-wide properties
Related concepts
Changing the system-wide properties programmatically
Verifying system properties