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

Document ID : KB000011956
Last Modified Date : 14/02/2018
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Introduction:

IBM send out a Red Alert Notification on November 4th.

- TITLE: Update to 2016.11.02 z/OS V2R2 VTOC Alert

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

- URL: http:http://www14.software.ibm.com/support/customercare/sas/f/redAlerts/20161104.html

 

Question:

Are there any CA-Allocate implications ? 

We took the local fix option of setting SSR Disabled. Are there any CA-Allocate implications in doing this ? 

Environment:
VTOC 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 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.Recommended Actions:Disable z/OS SSR function of Device Manager until fix for APAR OA51499 is available (instructions below).Please note: If recent PTF UA82730 is applied then you must remove this PE PTF or apply ++APAR for OA51474 prior to disabling SSR. Please see APAR OA51499 Local Fix for additional details.Disabling z/OS SSR:Issue z/OS Command F DEVMAN,DISABLE(SSR) for current IPL? ? ? ? ? ? ? ? ? ? ? ? ? -or-Update DEVSUPxx parmlib member to include DISABLE(SSR) and issue z/OS command SET DEVSUP=(xx,yy) or SET DEVSUP=xx to all systems to persist across IPL's.
Answer:

CA Allocate, when correctly configured, will eliminate any x37 abend.

If a specific E37 abend does occur due to an environmental event out of the control of CA Allocate, then the VTOC error condition described by the IBM RED ALERT could occur. 

CA Allocate does not directly update the VTOC on a volume.

Additional Information: