DCMT VARY ZIIP

DCMT VARY ZIIP varies the CA IDMS usage of the zIIP engines on or off.
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DCMT VARY ZIIP varies the CA IDMS usage of the zIIP engines on or off.
This article describes the following information:
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Syntax
The following example shows the syntax for DCMT VARY ZIIP:
►►─ DCMT ───────Vary ZIIP ─┬── ONline ─┬───────────────────────────────────────────►◄                            └─ OFFline ─┘
Parameters
Following are the parameters for DCMT VARY ZIIP:
  • ONline
    Varies the use of the zIIP processors online
  • OFFline
    Varies the use of the zIIP processors offline
Usage
Use zIIP Processor Depending on System Activity
Varying the zIIP engine can be used to adjust your system based on the workloads being processed. When heavy user program workload increases, such as ADS programs, you can vary zIIP usage OFFline to eliminate overhead caused by swapping. A message is written to the log indicating whether zIIP is varied offline or online.
Considerations
You need to be familiar with the following information before using the DCMT VARY ZIIP command:
  • CA IDMS must be brought up with the IDMS Parameter ZIIP=Y to enable varying zIIP on/off.
  • If RHDCOMVS or a Nucleus module is loaded from an unauthorized load library during CV startup, CA IDMS turns off the zIIP engine and it cannot be varied back on. After you move the RHDCOMVS or Nucleus module to an authorized load library, you must cycle the CV to reinstate the use of zIIP.
  • CA IDMS suspends zIIP processing if any of the following program types are loaded from an unauthorized load library during normal CV operation. The 'DCPROFIL' task shows "U" (unauthorized) as the zIIP designation:
    • SQL procedures
    • User Exits
    • Database procedures
    • IDMS Nucleus modules
    zIIP suspension allows zIIP to be turned back on. Before you re-enable zIIP, follow these steps:
    1. Verify that the program does not contain malicious content.
    2. Move the program to an authorized library.
    3. Flag the program for reload, using DCMT VARY PROGRAM or .DCMT VARY NUCLEUS v19_Next.
Security risk warning: 
The Database or Security Administrator needs to check the unauthorized module before moving it to an authorized library.  If a check is not done and zIIP processing is re-enabled, you run a significant security risk and may allow malicious content to spread throughout your z/OS system environment.
We highly recommend that the use of the DCMT VARY ZIIP command is tightly controlled. CA IDMS/DC permits the assignment of a discrete security class to each of the DCMT commands, allowing the administrator to limit the use of the VARY ZIIP command to authorized persons only. For more information about discrete security for the DCMT task, see Administrating Security for IDMS.
Examples
The following example shows DCMT Vary ZIIP OFF.
DCMT VARY ZIIP OFF IDMS DC302000 ZIIP VARIED OFF
The following example shows DCMT Vary ZIIP ON.
DCMT VARY ZIIP ON IDMS DC302002 ZIIP VARIED ON