Managing file systems

DFSMS manages the location of all file systems on volumes. However, a file system can outgrow the space on its volume and need more space. Or activity in a file system can become so great that it slows response time. In these cases, the file system needs to be managed.

File systems can span volumes. As users add files and extend existing files, each data set can increase in size to a maximum of 123 extents if secondary extents are specified in the allocation. The system programmer can:
  • Remove other data sets from the volume on which the full volume condition resides.
  • Move individual UNIX files and subtrees to other volumes.
  • Move the entire full file system to another file system.
The storage administrator or system programmer can monitor the space in a file system by mounting a file system with the FSFULL parameter. For example, you would see message IGW023A when the file system is 70 percent full. Then it would issue another message when the file system is 80 and 90 percent full:
mount parm('FSFULL(70,10)')

You can set up read-only basic partitioned access method (BPAM) access to UNIX files, including HFS, zFS, NFS, and TFS files. Each z/OS UNIX directory is treated as if it were a PDSE or PDS directory. For more information about BPAM access to z/OS UNIX directories, see z/OS DFSMS Using Data Sets.