Setting the limits for CICS storage

Use the z/OS® REGION and MEMLIMIT parameters to set limits for the storage for the CICS® region. Use the CICS DSALIM and EDSALIM system initialization parameters to limit the total storage for the CICS dynamic storage areas (DSAs) in 24-bit and 31-bit storage.

About this task

The z/OS REGION and MEMLIMIT parameters specify the amount of virtual storage for the address space in which the CICS region runs.
  • Use the z/OS REGION parameter to specify the amounts of 24-bit (below-the-line) and 31-bit (above-the-line) storage that are requested for the CICS region.
  • Use the z/OS MEMLIMIT parameter to set the limit for the amount of 64-bit (above-the-bar) storage for the CICS region.

    The 64-bit storage specified by the MEMLIMIT value includes the CICS dynamic storage areas above the bar (the GDSA) and MVS storage in the CICS region outside the GDSA.

For more information about these parameters, see CICS region size.

The storage specified by the REGION value includes the storage specified by the CICS system initialization parameters DSALIM and EDSALIM. These parameters determine the overall limits within which CICS can allocate storage for the CICS DSAs.
  • Use the DSALIM parameter to set overall limits for the CICS DSAs in 24-bit (below-the-line) storage.
  • Use the EDSALIM parameter to set overall limits for the extended dynamic storage area (EDSA), that is, the CICS DSAs in 31-bit (above-the-line) storage.
CICS allocates individual dynamic storage areas automatically, and you do not need to specify their sizes. CICS varies the size of the individual dynamic storage areas as the need arises.
  • CICS allocates DSAs in 24-bit storage within the limits set by DSALIM.
  • CICS allocates DSAs in 31-bit storage within the limits set by EDSALIM.
  • CICS allocates DSAs in 64-bit storage within the limits set by MEMLIMIT.

Procedure