Modifying the SYS1.PARMLIB IGDSMSxx member

The IGDSMSxx parmlib member includes the following parameters to support the CF and VSAM RLS processing:

• CF_TIME, which aligns creation of all the CF-related SMF type 42 records with subtypes 15, 16, 17, 18 and 19
• DEADLOCK_DETECTION, which specifies the interval for detecting deadlocks between systems
• RLSINIT, if YES, specifies whether the SMSVSAM address space is started as part of system initialization or by the V SMS,SMSVSAM,ACTIVE command. If you specify NO, to start SSVSAM later, you must do the following: change RLSINIT to YES, issue the SET SMS=xx command, then IPL or issue the V SMS,SMSVSAM,ACTIVE command. The default is NO.
• RLS_MaxCfFeatureLevel, which specifies the method VSAM RLS caching uses to determine the size of the data that is placed in the CF cache structure.
• RLS_MAX_POOL_SIZE, which specifies the maximum size of the SMSVSAM local buffer pool
• RlsAboveTheBarMaxPoolSize, which specifies the maximum amount of virtual storage above the 2-gigabyte bar that can be used for VSAM RLS buffering.
• RlsFixedPoolSize, which specifies the amount of real storage (both above and below the 2-gigabyte bar) to be dedicated to VSAM RLS buffering.
• SMF_TIME, which aligns the SMF type 42 records for DFSMS (with subtypes 2, 15, 16, 17, 18 and 19) to the SMF_TIME interval
• USEEAV, which specifies at the system level, whether SMS is to select extended address volumes during volume selection processing. This check applies to new allocations and when extending data sets to a new volume. You can enter an operator command to change the value of this keyword.

  NO

  This is the default. SMS does not select extended address volumes during volume selection.

  Setting USEEAV to NO has the following implications:

  • Data sets might still exist on extended address volumes in either the track-managed or cylinder-managed space of the volume.
  • In addition, when you specify or default to USEEAV=NO, the system skips EAV volumes for the following functions to avoid the failure of DFSMShsm requests:
    • Recall
    • Migration to an ML1 or ML2 DASD volume
    • Backup
    • Recover
    • ARECOVER
    • Daily backup volume / backup volume spill process
  • When a system where USEEAV is set to NO backs up a data set from an EAV, the data set will be recovered to a non-EAV volume and the vendor attributes will be lost. The system issues message ARC0784I in this case.

  YES

  SMS is to use extended address volumes to allocate new data sets or to extend existing data sets to new volumes.

  Note: When SMS is not active, USEEAV is not available and the installation must use alternate means to control the usage of EAVs.
• BreakPointValue, which specifies the number of cylinders (0-65520) that SMS uses to select volumes for VSAM data sets. The default is 10. When SMS is not active, the system assigns the default value.

You can modify these parameters at any time during VSAM RLS processing. For more information, refer to Changing IGDSMSxx parameters to support the coupling facility. For more information about the IGDSMSxx member, refer to the topic about IGDSMSxx in z/OS MVS Initialization and Tuning Reference.