Changing zFS attributes on a mounted zFS compatibility mode file system

zFS attributes are assigned to a zFS compatibility mode file system when it is mounted. The attributes can be set by specifying a zFS MOUNT PARM or they can be set from the zFS default values of the system where the primary mount occurs. These attributes, which are generally only meaningful for read/write mounted file systems, include the following:
  • AGGRFULL
  • AGGRGROW
  • CONVERTTOV5
  • FSFULL
  • RWSHARE
  • NORWSHARE

These attributes typically remain with that file system until it is explicitly unmounted. When all systems are at z/OS V2R3, some of these attributes can be changed dynamically with the zfsadm chaggr command. Otherwise, they can only be changed when the file system is unmounted and remounted, as indicated in the rest of this section. For more information about zfsadm chaggr, see zfsadm chaggr.

If the file system's attributes were assigned from a zFS default set on the system, they can be changed in the following situations:
  • The file system is NORWSHARE and z/OS® UNIX ownership moves to another system with a different zFS default.
  • The file system is remounted samemode and the z/OS UNIX owning system has a different default.
  • The file system is remounted from read-only to read/write and the z/OS UNIX owning system has a different default.
  • The file system is NOAUTOMOVE and the system is coming up with a different default.

The RWSHARE and NORWSHARE attributes of a compatibility mode file system may also be changed if they were assigned from a zFS default of the system on which they were mounted.

For example, there are several cases when the RWSHARE attribute of a file system may be changed to NORWSHARE:
  • The file system is remounted from read-only to read/write and the z/OS UNIX owning system has a NORWSHARE default.
  • The file system is NOAUTOMOVE and the system is coming up with a NORWSHARE default.
Similarly, if the NORWSHARE attribute was assigned from a zFS default, it may be changed to RWSHARE under the following situations:
  • The file system has z/OS UNIX ownership moved to another system that has specified RWSHARE as the default.
  • The file system is remounted from read-only to read/write and the z/OS UNIX owning system has an RWSHARE default.
  • The file system is NOAUTOMOVE and the system is coming up with an RWSHARE default.
You can query the current default value of a zFS attribute by issuing the zfsadm configquery command. For example, to query the default value of the following attributes, you can issue the following commands: 
zfsadm configquery -aggrfull
zfsadm configquery -converttov5
zfsadm configquery -fsfull
zfsadm configquery -aggrgrow
zfsadm configquery -sysplex_filesys_sharemode

You can change a zFS attribute on a mounted file system. To do so, take an appropriate action, as previously described for the attribute that you want to change. For example, to change the NORWSHARE attribute of a compatibility mode file system to RWSHARE, you can move the z/OS UNIX ownership of that file system to a different system that specifies RWSHARE as the zFS default.

Also, as the following examples show, you can change the zFS default values by issuing the zfsadm config command: 
zfsadm config -aggrfull 95,5
zfsadm config -converttov5 on
zfsadm config -fsfull 90,10
zfsadm config -aggrgrow on
zfsadm config -sysplex_filesys_sharemode rwshare
Tip: Generally, to avoid getting unexpected attribute changes, it is best to have the zFS default values be the same on all members of the sysplex. However, if you want to change an attribute of a mounted file system, you can temporarily change a zFS default and then cause one of the situations that were previously described. For example, move the z/OS UNIX ownership of the file system to a different system where the zFS default has been temporarily changed, then change the default back to the original value. You can only change a zFS attribute of a mounted file system if you did not specify the attribute in a MOUNT PARM.