File system size increases as users add files and extend existing files. Eventually, a file system can outgrow the space on its volume. In this case, the storage administrator or system programmer responsible for HFS data sets can either make more space available on the volume by moving individual HFS files to other file systems that have space available, or do one of the following:

• Move the entire file system to another set of volumes as follows:
  1. Have an authorized user enter a TSO/E UNMOUNT command to logically unmount the file system.
  2. Allocate an HFS data set with a different data set name on a volume, or set of volumes, that has adequate space available.
  3. Use the DFSMSdss DUMP function to logically dump the old file system.
  4. Use the DFSMSdss RESTORE function to restore the dumped file system with a new name to a volume, or set of volumes, that has sufficient space. If you want to maintain the original file system name, delete the existing file system first, and then restore it using DFSMSdss without renaming it.
• Remove files from the file system by either deleting them or by moving them to another file system. If it is impossible to remove the chosen files from a particular directory in the file system, it may be possible to remove other files from a different directory in the same file system. The objective is to reduce the size of the file system.
• Create a new file system on another volume, or set of volumes, and move some files from the full file system to the new file system. To avoid problems that can result from this approach, define symbolic links using the original names.
• Add another volume to the file system candidate volume list with the IDCAMS ALTER ADDVOLUMES command. The file system must be unmounted and remounted for the additional volumes to be usable by the HFS.
• The storage administrator or system programmer can monitor the space in a file system by mounting an HFS with parm FSFULL. For example, mount parm('FSFULL(70,10)') will cause HFS to issue message IGW023A when the file system is 70 percent full and then issues an additional IGW023I messages when the file system is 80 and 90 percent full.

The BPX1PCT callable service can be used to extend the file system (see Using pfsctl (BPX1PCT) Physical File System Control for HFS.