From my earlier post:
From the VSAM Demystified redbook, SG24-6105:Extended format data sets must be system-managed. A system-managed data
set must have an associated storage class and reside in a system-managed
volume. Extended format data sets are described in the catalog as striped data
sets with a stripe count of one. When a data set is allocated as an extended
format data set, the data and index are extended format. Any alternate indexes
related to an extended format cluster are also extended format.
Note the Redbook says an extended format VSAM file must:
1. have an associated storage class
2. reside on a system-managed volume
The data class is a necessary but far from sufficient condition to allocate an extended format VSAM file. You must make sure you define a storage class in your ACS routines that will cover the data set you are attempting to allocate, and you must make sure you are allocating on a system-managed volume (that is, when ICKDSF is run to initialize the volume, the keyword SG must be present as one of the initialization parameters). Furthermore, the presence of this message from your post is a red flag that you have work to do:
IGD06023I STORAGE GROUP HFSCLASS IS NOT REFERENCED BY THE STORAGE GROUP ACS ROUT