Red Alert : potential exposure for loss of data or data set corruption for DFSMS VSAM/RLS users on z/OS 1.13

Well, life goes on, even after the announcement of a new system. Here's a new Red Alert:

Potential exposure for undetected loss of data or data set corruption for DFSMS VSAM/RLS users on release z/OS 1.13

Users affected:
All zOS 1.13 (HDZ1D10) VSAM/RLS users who are sequentially erasing records from a KSDS while simultaneously updating records via a concurrent request.

Products affected:
zOS 1.13 DFSMS VSAM/RLS (HDZ1D10)

Description:

It is possible for an inserted or updated record to be unintentionally erased or down leveled if concurrent RLS access of a KSDS has sequential erase activity and inserts/updates taking place at the same time. In order for data to be lost, at least one sequential erase must remove all records in a CI, such that CI reclaim is initiated for that CI. Subsequent sequential requests may then overlay other updates to the data set, causing the previously updated records to be lost. The job that updated the record may not receive an error indication, or may receive unexpected logic errors such as record not found. EXAMINE may also report key sequence errors.

Please see APAR OA40253 for additional information and actions to determine exposure.

Recommended Actions:
Apply ++APAR for OA40253.

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