Enhancement to System Managed Storage* to remove the need to specify the size of a dataset and bypass the current limitation on a datasets maximum size determined by the limited number of extents a dataset can have.
Original Publication Date: 2001-Dec-16
Included in the Prior Art Database: 2003-Jun-20
The definition of a Storage Group should be enhanced to include an EXTENT SIZE. All extents, of all datasets allocated to this Storage Group will use this as both their Primary and Secondary Extent Size This will not be over-writable by the user. The Storage Group will have an EXTENT TRIGGER LEVEL. and a RELATED STORAGE GROUP. Once the number of extents allocated to a Dataset in the Storage Group hits the EXTENT TRIGGER LEVEL the Dataset will be automatically migrated to the RELATED STORAGE GROUP This storage group will be the same as the datasets current storage group except it's EXTENT SIZE will be significantly larger. Therefore, once moved the dataset will have had it's total number of extents reduced and will hence be able to continue to grow. This process will be undertaken by separate tasks, in the same way datasets are migrated to other storage Mediums (Level 1 and Level 2). The EXTENT TRIGGER LEVEL should be set low enough that a dataset can still grow (should it need to before the opportunity to migrate it occurs). Datasets can be assigned an INITIAL STORAGE GROUP and a MAXIMUM STORAGE GROUP effectively setting their Upper and Lower sizes. They will initially be allocated in their INITIAL STORAGE GROUP and use it's EXTENT size etc. They will not be allowed to migrate beyond their MAXIMUM STORAGE GROUP This will prevent "runaway datasets" from consuming excess dasd.