Resolution:
Access errors in a newly created or restored segment.

Environment:
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o All z/OS versions of Object Service Broker.

Symptoms:
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On a newly created segment access errors are reported when you try to read/write segment data. A msg is produced in the DOB log.

S6BDB004W-cccc VSAM HEX REQ=00 RC=08 FB=68 R15=nnnnnnnn RBA=nnnnnnnn

Cause:
======
The problem is caused by the ESDS cluster definition being given the EXTENDED attribute. This is done via the dataclass definition and can be picked up, due to a dataclass change, without the knowledge of the DBA.  

Resolution:
===========

Do not set the EXTENDED arttribute for OSB cluster definitions. I.e. select a dataclass that does not set this attribute.

N.B. the Term EXTENDED is severely overloaded.  There are 3 different meanings to the same word.

1) When a dataset becomes full it is EXTENDED and takes up another extent on DASD.

2) On very large virtual DASD devices. The EXTENDED attribute is used to define which datasets can exist in the extended addressing space (EAS) at the end of the volume.

3) The VSAM EXTENDED attribute is used to describe a VSAM cluster that, amongst other things, can grow to more than 4GB in size.

We are talking about item 3. The setting of the the VSAM EXTENDED attribute will show the word EXTENDED on a LISTCAT ALL of the cluster.

S6BDB004W message with RC=08 FB=68 on extended format vsam segment datasets.