If you need a DCSS that is defined with special options, you must use a workaround to
save the DCSSs.
Before you begin
Important: This section applies to DCSSs with special options only. The workaround in
this section is error-prone and requires utmost care. Erroneous parameter values for the described
CP commands can render a DCSS unusable. Use this workaround only if you really need a DCSS with
special options.
Procedure
Perform the following steps to save a DCSS with optional properties:
- Unmount the DCSS.
Example: Enter this command to unmount a DCSS with the device node
/dev/dcssblk0:
# umount /dev/dcssblk0
- Use the CP DEFSEG command to newly define the DCSS with the required
properties.
Example: Enter this command to newly define a DCSS,
mydcss, with the range
80000-9ffff, segment type
sr, and the
loadnshr operand:
# vmcp defseg mydcss 80000-9ffff sr loadnshr
Note: If your DCSS device maps to multiple DCSSs as defined to z/VM, you must perform this step for each DCSS. Be sure to specify
the command correctly with the correct address ranges and segment types. Incorrect specifications
can render the DCSS unusable.
- Use the CP SAVESEG command to save the DCSS.
Example: Enter this command to save a DCSS
mydcss:
# vmcp saveseg mydcss
Note: If your DCSS device maps to multiple DCSSs as defined to z/VM, you must perform this step for each DCSS. Omitting this step
for individual DCSSs can render the DCSS device unusable.
Reference
See z/VM: CP Commands and
Utilities Reference, SC24-6268 for details about the DEFSEG and SAVESEG CP commands.