Red Alert - TWO IMPORTANT RECOMMENDATIONS FOR z/OS V2R2 USERS

Date: 2016.11.02

Title:

TWO IMPORTANT RECOMMENDATIONS FOR z/OS V2R2 USERS

Abstract #1:

Potential for z/OS V2R2 JES2 (HJE77A0) members unable to WARM start.

Users Affected:

Systems running z/OS V2R2 that have the JES2 Checkpoint residing on DASD -and- running in DUAL mode (CKPTDEF MODE=DUAL)

Description:

For systems that meet the above criteria, JES2 uses a change log to contain a summary of updates since the previous checkpoint cycle. JES2 may encounter I/O errors ($HASP291) and/or abends (S18A) when attempting to read in a large valid checkpoint change log. A checkpoint I/O reconfiguration will be triggered in this case, however potential overlays of JES2 private storage from the original error may result in unpredictable errors after exiting the reconfiguration.

Any z/OS V2R2 JES2 member in the multi-access spool (MAS) will not be able to read the checkpoint containing a large valid change log without encountering abends. z/OS V2R1 JES2 members in the MAS will be able to read the checkpoint appropriately, but the z/OS V2R2 members will not be able to WARM start. If the entire MAS is comprised of z/OS V2R2 members, then no member will be able to process the checkpoint and this may result in a required COLD start.

Please see APAR OA51558 for additional details.

Recommended Actions:

For users that meet the above criteria, checkpoint should be switched to DUPLEX mode (CKPTDEF MODE=DUPLEX) to avoid the situation.

Abstract #2:

Potential for loss of access to data on a volume due to erroneous 'End of File' written to the VTOC or VTOCIX on z/OS V2R2 DFSMS (HDZ2220)

Users Affected:

Systems running z/OS V2R2 with DFSMS Secondary Space Reduction (SSR) function enabled (default)

Description:

For systems with DFSMS Device Manager Secondary Space Reduction enabled, the VTOC or VTOCIX may be updated incorrectly if an AbendE37 occurs when no storage space is available while trying to extend to secondary extents on a new volume.

Please see APAR OA51499 for additional details as new information is made available

Recommended Actions:

Please disable z/OS Secondary Space Reduction function of Device Manager until fix for APAR OA51499 is available as follows:

                          -or-  

• - Issue z/OS Command F DEVMAN,DISABLE(SSR) for current IPL
• - Update DEVSUPxx parmlib member to include DISABLE(SSR) and issue z/OS command SET DEVSUP=(xx,yy) or SET DEVSUP=xx to all systems.

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