Volume considerations

Merging volumes and VTOC sizing considerations
Although zDMF facilitates the consolidation of data sets from multiple smaller volumes to larger volumes, zDMF does not resize VTOCs for the additional metadata that will reside on a larger volume.
Hard-coded volume references
You must take into consideration instances where the catalog is not the only mechanism used to locate data sets, as part of your migration planning. Storage environments with comprehensive storage management policies implemented by DFSMS or another storage management facility are heavily reliant on the catalog environment to access data sets.
Extended Address Volumes (EAV)
zDMF supports Extended Address Volumes (EAV), that is, volumes with more than 65520 cylinders. EAV is supported on z/OS® 1.10 and higher. On EAV, cylinder numbers less than or equal to 65520 are designated track-managed space and cylinder numbers greater than 65520 are designated cylinder-managed space or extended addressing space (EAS).
Target volumes
ALL target volumes must have an additional 10 cylinders of contiguous free space in the track managed area of the volume to allocate a zDMF extent map file. The extent map file is allocated the first time a target data set is allocated on a target volume.

Parent topic: Planning and implementation