FDDRL subtasks

If the FDDRL parameter PROCESS-JOBS=*BY-SUBTASKS is set (default), the FDDRL jobs are executed under FDDRL subtasks. The subtasks for executing the FDDRL jobs are started by the //START-JOBS statement.

You can specify the degree of parallelism using the FDDRL parameter TASK-LIMIT.

A separate FDDRL subtask is generated for each save entity (single disk or disk set). The subtasks process the jobs of their save entity:

• With the single disk save entity, precisely one disk is processed.

• With the disk set save entity, each subtask processes multiple disks; the jobs for disk processing are assigned dynamically to each subtask.

The FDDRL subtasks have the following attributes:

• FDDRL subtasks are treated like batch tasks in BS2000, but without SYSDTA and SYSCMD environments.

• FDDRL subtasks receive the same user ID (TSOS) and account number as the FDDRL main task.

• FDDRL subtasks inherit the password table of the main task. The passwords of tapes can be specified under the main task (/ADD-PASSWORD).

• The job class of the FDDRL subtask is the same as that of the FDDRL main task. If this job class is not permitted for batch tasks, the FDDRL subtask is started under the default job class for batch tasks.

• The task category of the FDDRL subtask is the same as that of the FDDRL main task. If this task category is not permitted for batch tasks, the default category of the job class is used.

• The job name of the FDDRL subtask is controlled by the value of the FDDRL Parameter JOB-NAME:

  • By default (JOB-NAME=*STD), the job name of the FDDRL subtask is generated either from the VSN of the disk or from the name of the disk set, depending on the save entity:
    A VSN is preceded by the “$”character. Each illegal character in the job name, such as a period “.” or hyphen “-”, is replaced by the “#” character.

    Exception

    If the job name of the main task is called “MARENTST”, the subtask is also given this job name (support for MAREN test mode).

    Examples

    For the disk ABC.01 the job name $ABC#01 is created. You can display the job status for this FDDRL subtask using the following command: /SHOW-JOB-STATUS JOB-NAME=$ABC#01.

    The pubset FDL is restored using SAVE-ENTITY=*DISK-SET. You can display the job status for this FDDRL subtask using the following command: /SHOW-JOB-STATUS JOB-NAME=FDL#1.

  • If specified JOB-NAME=*SAME the FDDRL subtask get the same name as the maintask.

  • If a jobname is specified  (JOB-NAME=<name 1..8>), the FDDRL subtask gets this name

  
  

• The FDDRL subtask receives the task priority that was specified with the RUN-PRIORITY parameter. The permitted limit values of the job class are automatically respected.

• If you have specified the behavior of FDDRL V18.0 with the REPORT-FILE=*NONE operand in the //MODIFY-FDDRL-PARAMETERS statement, the outputs of the FDDRL subtasks and their messages to console are logged to SYSOUT. After subtask start, SYSOUT is assigned to the following file:

  • S.FBD.<stsn>.<yyyy-mm-dd>.<mtsn>.<vsn> (single disk save entity)

  • S.FBD.<stsn>.<yyyy-mm-dd>.<mtsn>.<dset> (disk set save entity)

  with the following meanings:

  <stsn>	is the task sequence number (TSN) of the subtask
  <mtsn>	is the task sequence number (TSN) of the main task
  <vsn>	is the volume serial number of the disk
  <dset>	disk set name

• If the FDDRL parameter REPORT-FILE=*STD is set, the outputs of the subtasks and their messages on the console are transferred to the log file of the FDDRL job at the end, the original SYSOUT files of the subtasks are then deleted.

• The FDDRL subtasks are monitored by the FDDRL main task during their execution. Their status can be output periodically in accordance with the STATUS-OUTPUT-PERIOD parameter (see chapter "Status output on the FDDRL subtasks").

• If FDDRL processing is performed under subtasks, disk and tape devices may not be reserved by the user under the main task with the /SECURE-RESOURCE-ALLOCATION command since this reservation cannot be passed on to the subtasks. Devices reserved in this way would be blocked for the subtasks.

Adjusting the number of FDDRL subtasks

Precisely one FDDRL subtask is generated per save entity (single disk or disk set). The FDDRL parameter TASK-LIMIT specifies how many of these FDDRL subtasks are to be active simultaneously. (Additionally, the number of parallel FDDRL subtasks can be limited by the job class limit for all batch jobs of their class)

By default, the task limit is set to four FDDRL subtasks. However, you can adjust this value to your requirements within the range 1 through 16 using the TASK-LIMIT parameter of the //MODIFY-FDDRL-PARAMETERS statement. You may need to adjust the value for the following reasons:

• To control system utilization – especially with respect to input/output.

• The number of parallel save runs is adjusted to match the available tape devices. Tape devices must therefore remain free so that

  • they can be used for premounting backup volumes (see chapter "Automating FDDRL saves").

  • any volume initializations that become necessary can be carried out.

  • they can be “reserved” for other applications.

• To permit multiple disk sets to be saved to their own tape sets in parallel when the disk set save entity is used, the task limit must at least be equal to the number of disk sets.