Subsystem parameters

Subsystem parameters are settings that apply to a Db2 for z/OS® subsystem. For example, the AUTH subsystem parameter controls whether Db2 checks authorizations. Many users colloquially refer to subsystem parameters as zparms.

Generally, system administrators set the value of subsystem parameters when they install or migrate Db2. After installation or migration, a system administrator can change the values of subsystem parameters if needed. However, because these parameters can affect the entire subsystem, system administrators should first carefully evaluate and plan for the impact of any changed values. In some cases, changing the value of a subsystem parameter requires Db2 to be stopped and restarted.

Most subsystem parameters are listed on installation panels. However, some parameters are not. For a list of subsystem parameters, including those parameters that are not on panels, see Directory of subsystem parameters, panel fields, and application default values. This list includes important characteristics of each parameter, including whether changing a the parameter requires you to stop and restart Db2.

Subsystem parameter values are contained in a load module that is generated by installation job DSNTIJUZ. The name of this subsystem parameters load module is specified in the PARAMETER MODULE field of installation panel DSNTIPO3. The default name is DSNZPARM. However, to avoid naming conflicts with other members, you should use a different name. Sometimes the naming convention DSNZPxxx is used. In a data sharing environment, each member must have its own subsystem parameter load module.

One way to check the subsystem parameter values is to call stored procedure SYSPROC.ADMIN_INFO_SYSPARM by running sample job DSNTEJ6Z.

Some Db2subsystem parameters are considered security parameters. These parameters can be updated only by processes with a privilege set that includes installation SYSADM authority or SECADM authority. for more information, see Security parameters in Db2 for z/OS.