Using Multitasking

Multitasking, also called subtasking, provides performance improvement in copy jobs involving more than one object.

Additionally, using this feature of BMC AMI Copy with the Snapshot Copy feature allows a single copy job to coordinate caching with the BMC XBM utility, and then branch into multiple concurrent I/O tasks so that the total elapsed time, as well as the amount of cache needed, is significantly reduced.

BMC AMI Copy supports two modes of subtasking:

  • GROUP YES: With GROUP YES, you use multitasking requiring grouped initialization and termination processing.
  • GROUP NO: This mode is sometimes referred to as extended subtasking. With GROUP NO, you use multitasking without requiring grouped initialization and termination processing, and without the increased demands on system resources required by such processing.

Related topics

Using-GDGs-and-symbolic-variables-when-multitasking

MAXTASKS=(1,AUTO)

ACPPRTnn-data-sets

Both modes of subtasking are available for the following commands:

  • COPY INDEX
  • COPY INDEXSPACE
  • COPY TABLESPACE

You can mix GROUP NO and GROUP YES multitasking in a single COPY job. The ability to group and multitask image copies in BMC AMI Copy accomplishes elapsed time improvements compared to IBM Db2 COPY.

BMC AMI Copy also supports multitasking with the COPY IMAGECOPY command, which does not include the GROUP option in its syntax, but processes multitasking in GROUP NO mode.

The following commands are not eligible for subtasking:

  • MODIFY
  • OPTIONS
  • OUTPUT
  • QUIESCE
  • RECALL

This section contains the following topics:

 

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