Environmental conditions affecting data set separation

Under the following environmental conditions, SMS might not separate two data sets that are specified for required or preferred separation:

Allocation is not SMS-managed.
Allocation is performed on a system in the SMS complex that runs a prior version of SMS that does not support data set separation.
During switching or activation of an SMS configuration, the data set separation profile cannot be accessed or fails validation.
A service that is allocating a temporary data set name does not provide the real data set name to SMS.
Two data sets that are specified to be separated are allocated at the same time by two different tasks or two different systems. For performance reasons, SMS does not serialize data set allocations.
A volume is varied online during allocation.
An IODF change occurs during allocation.
A data set name that is not listed in the data set separation profile is specified during DFSMShsm recover.
A data set separation profile might have been modified after the configuration was activated. This can result in differences between the data set separation profile data set and the active copy of the data set separation profile.
SMS does not perform data set separation during RENAME.
SMS does not perform data set separation during DFSMShsm migration to level 1 or level 2 storage.
SMS does perform data set separation during DFSMShsm recall.
SMS does not perform data set separation during full volume image copy.

SMS might not issue the corresponding warning message IGD17372I in those cases where allocation was successful and data set separation was not honored.