Advanced Topics › How You Change the Status of Managed Devices (VARY) › How You Make a Device Unavailable for Allocation › OVERGENNED Parameter

OVERGENNED Parameter

There are two main differences between the OVERGENNED status and the NOTAVAILABLE status. The first difference lies in the way the devices are treated in allocation recovery. OVERGENNED devices are always eliminated from the offline device list in allocation recovery and cannot be selected by replying to an allocation recovery message. OVERGENNED devices can be made available for allocation again only by issuing the VARY NOTOVG command. NOTAVAILABLE devices are eliminated conditionally from the offline device list in allocation recovery based on the setting of the SETOPTION TPCF AUTOREPLY=(NOWAIT…) options. NOTAVAILABLE devices can be made available for allocation through replying with them to allocation recovery messages or issuing the VARY AVL command.

The second difference lies in the eligibility of the device. OVERGENNED devices may be optionally marked ineligible in the EDL based on the SETOPTION TPCF OVGINELIG parameter settings. NOTAVAILABLE devices are not marked ineligible in the EDL.

The status of OVERGENNED is usually given to devices that are to be unavailable for allocation for long periods of time. For example, the status of OVG should be used for addresses that are defined as tape device addresses but do not have tape devices attached. The status of NOTAVAILABLE is usually given to devices that are to be temporarily unavailable for allocation. For example, the status of NOTAVL should be used for devices that are temporarily unavailable due to maintenance.

By using the SETOPTION TPCF OVGINELIG={NO|YES|JOBRESV} command, you can dynamically control whether OVG devices are marked ineligible in the EDL. Marking OVG devices ineligible in the EDL makes them unavailable for allocation early in the allocation process. This affects the way a job behaves in the device allocation process and can eliminate jobs going into allocation recovery and being canceled during allocation recovery. Note that OVG devices are always removed from the offline device list in allocation recovery regardless of the setting of the OVGINELIG parameter.

Examples: OVERGENNED Parameter

• To make device 01A0 OVERGENNED on the local system, issue the following command:

  VARY 01A0 OVG LOCAL
  

• To make this device OVERGENNED on all systems, issue the following command:

  VARY 01A0 OVG GLOBAL
  

• To make this device available again on all systems, issue the following command:

  VARY 01A0 NOTOVG GLOBAL
  

More information:

How You Influence Device Selection