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

SETCACHE||||||||||||||||||||||||||||||||||||||||||||||||use DASD installation recovery procedures. If the pinned volumes have DASD fastwrite active, issue DASDFASTWRITE OFF and then DASDFASTWRITEPENDINGOFF to clear the pinned tracks and set DASD fast write off.DISCARDPINNED can also be used; follow DASD recovery procedures. If theprobable cause is NVS failed or disabled, fix the problem and reissue SETCACHENVS ON.Setting DASD Fast Write On for a VolumeSETCACHE DASDFASTWRITE ON activates DASD fast write for the specifiedvolume. The procedure to activate DASD fast write is:1. SETCACHE SUBSYSTEM ON2. SETCACHE DEVICE ON3. SETCACHE NVS ON4. SETCACHE DASDFASTWRITE ONCreating a Duplex Pair from Two Simplex VolumesThe procedure to create a duplex pair is:1. Identify the primary and secondary volumes2. Issue SETCACHE SUBSYSTEM ON3. Vary the target secondary volume offline to all systems4. SETCACHE NVS ON5. SETCACHE SETSECONDARY specifying the primary volume id and secondaryaddress6. SETCACHE DEVICE ON for the primary volume7. (optional) SETCACHE DASDFASTWRITE ONNotes:1. If DASD fast write or device caching was on for the primary volume beforeSETCACHE SETSECONDARY was issued, DASD fast write or device cachingis on for the pair after it is established.2. Device caching may be activated to speed up establishing the duplex pair.3. When you use dual copy to migrate from 3390 devices to RAMAC devices, aninvalid format 4 DSCB is created on the target device. An ICKDSF APAR mustbe installed to fix the format 4 DSCB. See your IBM representative for the latestservice level.4. If either volume was previously acquired by an LPAR and has not beenreleased, an error message is issued with text that states that the duplex paircould not be established because path-groups are not compatible.Changing 3990 and 9390 Cache and NVS Operating ModesThis discussion covers the various Storage Control SETCACHE commands and theresulting actions. The commands presented here are not arranged in any priorityand operate independently of one another.Setting Cache Off for the SubsystemSETCACHE SUBSYSTEM OFF sets normal caching off for the subsystem. Thefollowing actions occur:vvDevice caching, cache fast write, and DASD fast write stop. Device status, withrespect to each of these functions, is retained and the active functions resumewhen subsystem caching is set on. When DASD fast write and dual copy are seton together (fast dual copy), the data is destaged from NVS to both devices.Each duplex pair is set to suspended state on the first write operation to thepair. Also, any duplex pairs with out-of-synchronization cylinders are suspended334 z/OS V1R6.0 DFSMS Access Method Services for Catalogs