Question:
Why does system parameter IXSMSDEL need to be set to N (the default value) during a conversion from DFSMShsm to CA Disk ?
Answer:
System parameter IXSMSDEL needs to be set to N during the whole conversion phase from DFSMShsm to CA Disk.
Otherwise, IXMAINT would delete all the DSNINDEX records pointing to Backup or Archive data still pending conversion from HSM to CA Disk.
That means all the DSNINDEX records that have special Archive Key B00001 or M00001 indicating data still under HSM control would be deleted.