Creating new zFS files for /tmp and /u
Management of z/OS® UNIX file systems in z/OS is a complex area. This procedure provides a simplistic design for new file systems. Considerations such as space requirements and alternative mount points might require a more in-depth plan.
This z/OS ADCD provides fairly small file systems for the /tmp and /u directories. Small file systems can cause problems, particularly when you are installing z/OS software by using SMP/E, or when programs create large memory dumps on the z/OS UNIX file system. Allocate 100 primary cylinders and 20 secondary cylinders for these file systems. If the current file systems for /tmp and /u are not large enough, replace them. To create new file systems for /tmp and /u, create two new zFS files and associate these new files with the /tmp and /u directories. Catalog these two new zFS files on the xxCFG1 volume with your other customization. Since a user catalog named USERCAT.Z23x.USER is on the xxCFG1 volume of the z/OS 2.3 ADCD as shipped, it can be used for cataloging the two new zFS files. By avoiding use of the master catalog, during migration to a new z/OS ADCD, you then need only to import the user catalog and replicate the alias definitions so that catalog entries are restored. Use this procedure for creating new zFS files for /tmp and /u:
- Create aliases for the high-level qualifiers of the zFS files
- Create the zFS files
- Modify the appropriate BPXPRMxx parmlib member to mount the new zFS files with the /tmp and /u directories
- Copy the existing /tmp and /u directories to the new /tmp and /u directories that are mounted with the new zFS files
- Optionally create a new load parm to contain these changes
- Shut down the system and reIPL
The next topics describe the procedures for each step, including sample JCL where appropriate. In these procedures, the two z/OS UNIX file systems are created with a high-level qualifier of CUST on volume xxCFG1.