AUTO RESTORE - number of DMSAR tasks

Products

• Disk Backup and Restore - MVS

Issue/Introduction

Given the current Disk configuration in our installation, if a user or job requests the auto-restore of more than 50 files, 50 DMSAR task instances are launched to perform the restore.
Is there a parameter setting we can use to reduce this level of parallelism—for instance, so that if a user or job requests the auto-restore of 50 files, only 5 DMSAR task instances start executing, while the remaining files wait in a queue until they can be restored?

Resolution

In the standard Disk Backup and Restore environment, DMSAR auto-restore tasks are typically initiated dynamically based on the volume of requests. So we can not limit the number of DMSAR jobs from standard Disk.

The DMSAR requests from the Vantage (if used) can be controlled by the VKGPARMS MAXTASKS and ARDEDSRV . Here is the description of MAXTASKS parm.

MAXTASKS

Specifies the maximum number of Auto Restore started tasks allowed to run at the same time when parameter ARDEDSRV is set to (N). When ARDEDSRV is set to (N), MAXTASKS specifies the maximum number of DMSARs that can run simultaneously to serve outstanding restore requests. One DMSAR may serve one restore request at one time. When a restore request is completed, the DMSAR is ready for another request. Each restore request can contain one or more data sets from the same job (or several data sets, if the JES2 Exit6 issued the restore request). When ARDEDSRV is set to (Y), MAXTASKS is ignored.Applies to: Autorest (ARM)Range: 1 to 255Default: (1)