Optional Parameters

DEVICE|SUBSYSTEM|NVS|DASDFASTWRITE|CACHEFASTWRITE
specifies whether the command pertains to caching for a specific device or subsystem caching, nonvolatile storage, DASD fast write to a specific device, or cache fast write access for the subsystem.
DEVICE
specifies that access to the cache for a particular device is allowed or prohibited.
Abbreviation: DEV
Note:
  1. DEVICE OFF is not supported for the ESS.
  2. DEVICE ON or OFF can be issued to an offline device by using the UNITNUMBER parameter.
SUBSYSTEM
specifies that access to cache for the subsystem is allowed or prohibited.
Abbreviation: SUBSYS or SSYS
Note:
  1. SUBSYSTEM OFF is not supported for the ESS.
  2. SUBSYSTEM OFF can be issued to an offline device by using the UNITNUMBER parameter.
  3. READ access authority to the RACF® FACILITY class resource STGADMIN.IDC.SETCACHE.SUBSYSTEM is required to use the SUBSYSTEM parameter.
Attention: When cache operation is restored, SETCACHE RESETTODUPLEX must be issued for each suspended duplex pair in the subsystem.
NVS
specifies that access to the nonvolatile storage is allowed or prohibited.
Note:
  1. NVS OFF is not supported for the ESS.
  2. NVS OFF can be issued to an offline device by using the UNITNUMBER parameter.
Note:
DASDFASTWRITE
specifies that DASD fast write to a particular device is allowed or prohibited.
Abbreviation: DFW or DASDFW
Note:
  1. DASDFASTWRITE OFF is not supported for the ESS.
  2. DASDFASTWRITE ON or OFF or PENDINGOFF can be issued to an offline device by using the UNITNUMBER parameter.
CACHEFASTWRITE
specifies that cache fast write for the subsystem is allowed or prohibited.

Abbreviation: CFW or CACHEFW

ON|OFF|PENDINGOFF
specifies whether access is allowed or prohibited.
ON
specifies that access is allowed.
OFF
specifies that access is prohibited.
Note: Setting cache on or off for the subsystem and setting cache on or off for a device are independent operations. That is, cache can be set on or off for individual devices whether the cache is on or off for the subsystem. However, if the cache is set off for the subsystem, setting cache on for an individual device has no effect until the cache is set on for the subsystem.
PENDINGOFF
specifies a recovery command to allow cache or DASD fast write to a particular device to be set off when cache or DASD fast write is in pending state.
Abbreviation: PEND.
Note:
  1. This parameter should only be used as a last resort because no destage occurs and data could be lost.
  2. The PENDINGOFF parameter must be used with either SUBSYSTEM or DASDFASTWRITE, and is accepted only if SUBSYSTEM OFF or DASDFASTWRITE OFF failed. That is, when the PENDINGOFF parameter is used with DASDFASTWRITE, the device must be in the DEACTIVATION PENDING state. When the PENDINGOFF parameter is used with SUBSYSTEM, the subsystem must be in the DEACTIVATION FAILED state (see LISTDATA STATUS). Otherwise, the command is rejected.
  3. PENDINGOFF is not available for NVS. If NVS OFF does not obtain the desired result, issue a DASDFASTWRITE PENDINGOFF to each device where DASD fast write is in a deactivation pending state. NVS OFF should then work.
SUBCHSET(n)
Specifies the subchannel set number from 0 to 3 that the device number specified with the UNITNUMBEr resides in. Valid with the CACHEFASTWRITE optional parameter when the UNITNUMBER parameter is used.
Parent topic: SETCACHE Parameters