Stopping the DFSMSrmm subsystem

Before you can shut down the DFSMSrmm subsystem, you must wait until all current requests are completed and any outstanding requests are flushed from the request queues. All jobs that are processing and using tapes should be completed before you stop the subsystem to allow DFSMSrmm to record details of tape usage when a tape data set is closed. Before stopping the DFSMSrmm subsystem, stop the batch initiators to avoid failing a job that opens a tape data set. When you stop DFSMSrmm, it cannot successfully shutdown if another address space is using DFSMSrmm resources. For example, there might be an DFSMSrmm WTOR outstanding for a batch job. If DFSMSrmm shutdown is delayed, DFSMSrmm issues messages to inform you of the delay and to list the job names of the address spaces preventing shutdown. For example:

EDG0154I SHUTDOWN OF DFSMSrmm DELAYED BY ANOTHER ADDRESS SPACE
EDG0155I ADDRESS SPACE LIST BY JOBNAME:
         JOBNAME1 JOB2     JOB3    JOB4       JOB5  			
         NUMBER OF JOBNAMES DELAYING SHUTDOWN =    5

Also, DFSMSrmm cannot stop if inventory management is already running. If any long running task prevents DFSMSrmm from stopping, you can use this command to interrupt processing:

F DFRMM,CANCEL(TaskToken/HSKP)

First, issue the QUERY ACTIVE command to determine the task that is actually preventing the stopping of DFSMSrmm. If any requests are subject to HOLD processing, you must RELEASE or CANCEL them in order for DFSMSrmm to STOP. If you want to end long running tasks in order to STOP DFSMSrmm, issue the CANCEL command. You can use this command to display the status of the tasks:

F DFRMM,QUERY ACTIVE

You must decide whether to cancel the tasks that have been HELD or to release them. To allow the existing tasks to complete while preventing new tasks starting, issue:

F DFRMM,HOLD(NEW)

Then to release the tasks that are HELD, issue:

F DFRMM,RELEASE(ALL)

If you decide to cancel the tasks instead, issue:

F DFRMM,CANCEL(ACTIVE)

In either case, you can now stop the DFSMSrmm subsystem task by issuing:

P DFRMM

Except when DFSMSrmm is being shut down for recovery or formal changes to the z/OS® system, do not shut DFSMSrmm down unless you are quiescing the entire operating system. If DFSMSrmm is not present or active to validate tape requests, all tape usage is prevented to maintain volume integrity.

In some recovery situations, you might need to remove DFSMSrmm from the system. You can use the EDGRESET utility by issuing the S DFRMM,OPT=RESET command to remove DFSMSrmm functionality from the system. That means that DFSMSrmm does not process any subsystem requests, such as TSO subcommands, and recording and validation of tape processing, unless DFSMSrmm is restarted. When you issue the RESET option in an RMMplex or in a client/server environment, the DFSMSrmm subsystem interface is removed only on the system where the RESET is issued.

If you use the DFSMSrmm EDGRESET utility to remove DFSMSrmm from the system and allow tape mounts to be processed without a media management system, you must keep a record of all tape activity that occurs during this period so you can update the DFSMSrmm control data set at a later time. If you are collecting System Management Facility (SMF) records for tape activity, you could use these as a source of information for updating the control data set.

The following command examples use the default procedure name DFRMM. Your installation might have defined a different name. You could also use a name you specified on the START command with the name parameter.

Example: To shut down the DFSMSrmm subsystem, use the z/OS STOP command:

P DFRMM

Before stopping, DFSMSrmm processes all existing requests to completion. New requests are rejected. If an existing, queued request is for inventory management, it fails. You can use the command:

F DFRMM,CANCEL(TaskToken/HSKP/ACTIVE)

to interrupt any long running requests that are currently running. If inventory management is already running, or any tasks are already subject to HOLD processing, the z/OS STOP command is rejected.

Example: To manually quiesce the DFSMSrmm subsystem, use the z/OS MODIFY command:

F  DFRMM,QUIESCE

When you issue the quiesce command, DFSMSrmm completes any requests being processed. Queued requests are not processed until you issue a command to take DFSMSrmm from the quiesced state and reinitialization is completed. If you stop DFSMSrmm from the quiesced state and any requests are outstanding, message EDG1107D prompts you with your choices of action. If the quiesce command is issued while some local tasks are being held, the quiesce command is rejected, and message EDG1108E is received.

In a multi-host environment, conditions, which result in an automatic quiesce of DFSMSrmm (such as control data set errors from which DFSMSrmm cannot automatically recover), cause the quiesce on all hosts sharing the control data set. Only after all hosts have successfully quiesced can the control data set be recovered. Manually issuing a DFSMSrmm quiesce affects only the host on which you issue the command. If you want all hosts quiesced, you must issue the command on each host that is sharing the control data set.

Example: To remove DFSMSrmm, use the z/OS START command:

S DFRMM,OPT=RESET

You can use the RESET option even if your installation does not have RACF® or an equivalent security product installed.

You can restart the DFSMSrmm subsystem using appropriate options for running either without tape recording or with tape recording and validation. You do not need to IPL to revert back to full DFSMSrmm subsystem function.

The RESET option affects the system on which the command is issued.