Allocating recalled data sets to volumes

After the list of candidate volumes has been assembled from the installation exit, DFSMShsm or DFSMSdss requests that the data set be allocated to the first volume on the candidate list. If the allocation fails for lack of space, DFSMShsm or DFSMSdss requests allocation to the next volume on the list. If this allocation also fails for lack of space, DFSMShsm or DFSMSdss tries the next volume, and proceeds down the list until either a volume with adequate space is found, or all the volumes on the list have been tried.

When DFSMShsm is the data mover, a recall can fail even though enough total space exists on the volume if the space is too fragmented to allocate the total space for the data set in five extents.