Environment Control Commands

The environment control commands affect the status of the DB2 subsystem and the Distributed Data Facility. These commands commonly are issued only by the DB2 systems programmer, systems administrator, or DBA. A brief description of the environment control commands follows :

-START DB2	Initializes and establishes the DB2 subsystem
-START DDF	Starts the Distributed Data Facility
-STOP DB2	Stops the DB2 subsystem
-STOP DDF	Stops the Distributed Data Facility

Environment Control Command Guidelines

Before issuing environment control commands, be sure to review the following guidelines.

Control the Use of Environment Control Commands

Secure the environment control commands so that they are issued only by technically astute administrative areas.

Verify the Completion of START DB2 and STOP DB2

Make sure that the START DB2 command successfully completes by ensuring that access to DB2 is available using DB2I. Another way to verify that the START DB2 command was successful is to make certain that the started tasks for DB2 are active. The default names for these tasks are:

DSNMSTR	DB2 Master Region
DSNDBM1	DB2 Database Region
IRLMPROC	DB2 IRLM

Your installation probably has renamed these address spaces, but the names are probably similar.

Be sure that the STOP DB2 command successfully completes by ensuring that the started tasks for the subsystem being stopped are no longer active.

Verify the Completion of START DDF and STOP DDF

You can check the status of the START DDF and STOP DDF commands by monitoring the status of the DDF address space. (The default name of the DDF address space is DSNDDF .)

Use MODE(FORCE) Sparingly

Exercise caution before stopping the DB2 subsystem with the MODE(FORCE) parameter. The FORCE option terminates all active programs and utilities. As such, in-doubt units of recovery may result by forcing DB2 to stop in this manner. The MODE(QUIESCE) option allows all active programs and utilities to complete before DB2 is stopped.

When DB2 is stopped with MODE(FORCE) or MODE(QUIESCE) , only currently executing programs are affected. No new programs or utilities are permitted to run.