Many new applications in z/OS exploit z/OS UNIX and store data into the file system. Some customers have ported their applications over from other UNIX or NT platforms, but might not be familiar with the licensed programs available to back up those applications on the z/OS platform. Other customers have used MVS™ and z/OS for a while, and assume that the backup techniques that they use for their MVS data sets are adequate for z/OS® UNIX files as well. This topic addresses these issues and helps you plan your backup strategies for your file system data.

Guideline: The /dev file system contains character special files that are created on a per-demand basis. Backing up the /dev file system is not necessary because all files are created when first referenced. Avoid backing up the /dev file system because the pseudoterminal files (/dev/ttyp*) might not close correctly when the process is terminated. For example, pseudoterminal slave file attributes might not be restored on CANCEL flows if the /dev file system is quiesced when the close() is processed, which might result in ICH408I security error messages on subsequent open attempts. Consider mounting /dev as a TFS file system, which is typically not included in backup policies.