This month we’ll examine the Storage Class construct, which lies at the heart of System Managed Storage and specifies whether or not a dataset is SMS-managed. The two dozen attributes that can be specified in the Storage Class indicate ‘what the dataset needs’ in terms of performance and availability and directly influence volume selection. We’ll discuss the often-misunderstood topics of Guaranteed Space, Data Striping, and more, as well as demonstrating the use of ISMF to create, copy, delete, and report on Storage Classes and other SMS constructs.