z/OS V1R6.0 DFSMS Access Method Services for Catalogs

SETCACHE|||||||||||||||||||||||||||||||||||||||||||Using SETCACHEPACE(n)specifies the number of tracks from 1 to 255 that are to be copied withoutinterruption during the Storage Control copy operation to establish a duplexpair (SETSECONDARY); to establish a duplex pair from a suspended duplexpair (RESETTODUPLEX); or to reestablish a duplex pair from the primary of asuspended pair and a user-specified alternate (REESTABLISHDUPLEX).Specifying PACE(0) defines an uninterruptible (dedicated) copy operation.Specifying PACE(1) to PACE (255) defines the number of tracks to copy beforereleasing the device for any outstanding device activity (when there is no moreactivity, the copy of the next n tracks resumes). The default is 15 tracks.Note: Specify PACE(1) or (2) for optimum device availability. Using PACE(0)or a large PACE value may lock out other activity to the volume for along time.Setting Caching On for the SubsystemSETCACHE SUBSYSTEM ON enables normal caching for the subsystem. If cachestorage is disabled or in a pending state, the command fails.Note: Pinned data, a cache failure, or cache disabled for maintenance can causethe command to fail.Abbreviation: SETCSetting Caching On for a DeviceSETCACHE DEVICE ON sets caching on for individual devices. The prerequisitefor device caching is subsystem caching on. This command can fail due to pinneddata.Setting Cache Fast Write On for the SubsystemSETCACHE CACHEFASTWRITE ON sets cache fast write on for the subsystem.With cache fast write on for the subsystem, all caching volumes use cache fastwrite for any channel program specifying it. If cache fast write is not on for thesubsystem, the specification is ignored in channel programs that request it.Prerequisites for cache fast write are:v Subsystem caching onv Device caching onSetting Nonvolatile Storage On for the SubsystemSETCACHE NVS ON enables use of the nonvolatile storage for the subsystem andconnects the battery to the NVS.If the command fails, it may be due to:v Pinned datav NVS failurev NVS disabled for maintenance.If the probable cause is pinned data, use LISTDATA PINNED SUBSYSTEM orDEVSERV to identify which volumes in the subsystem have pinned data. Fix theproblem that is preventing destage, if possible. If the volume cannot be repaired,Chapter 31. SETCACHE 333