Mounting file systems using symbolic links

You can mount different file systems at a logical mount point that resolves to a different path name on different systems.

While $VERSION/ can be used to differentiate a path based on the version level of a system and $SYSNAME/ can be used to differentiate on each system, you can use special identifiers to mount file systems using symbolic links. These are $SYSSYMR/template and $SYSSYMA/template.

Restrictions: When mounting file systems using symbolic links, observe these restrictions:

Like $VERSION/ and $SYSNAME/, the identifiers need to be at the beginning of the link name.
Only the first occurrence of $SYSSYMR/ or $SYSSYMA/ in the link name is recognized as an identifier for which the remaining text requires substitutions. Any other identifiers after the first one will remain as is in the resolved linkname.
Text must follow a $SYSSYMR/ or $SYSSYMA/ in order for it to be recognized as a valid identifier with text containing symbols to be resolved.
Any system symbol in the symbolic link text that is recognized by the ASASYMBM service are resolved. However, only static system symbols should be used in order to avoid unexpected results. These symbols are assigned a value at initialization. For information about system symbols, see z/OS MVS Initialization and Tuning Reference.

Tip: You can use D SYMBOLS to display the current settings of system symbols.

These examples assume that the standard MVS™ symbol &SYSR1. resolves to OSV315 on SY1 and resolves to OSV315B on SY2.

If the symbolic link is /x/y/sym1, and the symbolic link contains $SYSSYMR/&SYSR1./resdir, a path name lookup on /x/y/sym1 from SY1 will resolve the symbolic link to OSV315/resdir. Because it is a relative path name (the identifier was $SYSSYMR/), the resulting path name will be /x/y/OSV315/resdir.
Example: On a mount, passing /x/y/sym1 as the input mount point path name, the mount point would be: /x/y/OSV315/resdir on SY1.
- If the symbol &SYSR1. resolves to OSV315B on SY2, a lookup of the same path name would result in a mount point of /x/y/OSV315B/resdir.
- On a v_readlink syscall, passing the VnToken for the symbolic link, the output linkname would be OSV315/resdir on SY1 or OSV315B/resdir on SY2.
If the symbolic link is /x/y/sym1, and the symbolic link contains $SYSSYMA/&SYSR1./resdir, a path name lookup on /x/y/sym1 from SY1 will resolve the symbolic link to /OSV315/resdir. Because it is an absolute path name (the identifier was $SYSSYMA/), the resulting path name will be /OSV315/resdir.
Example: On a mount, passing /x/y/sym1 as the input mount point path name, the mount point would be /OSV315/resdir on SY1.
- If the symbol &SYSR1. resolves to OSV315B on SY2, a lookup of the same path name from SY2 would result in a mount point of /OSV315B/resdir.
- On a v_readlink syscall, passing the VnToken for the symbolic link, the output linkname would be /OSV315/resdir on SY1 and /OSV315B/resdir on SY2.