To enable channel subsystem priority queuing, you'll need to do
the following:
- In the WLM ISPF application, make sure that
I/O
Priority Management
is set to YES on
the Service Coefficients/Service Definition panel. - If your CPC is partitioned, click the Change LPAR I/O
Priority Queuing icon in the Primary Support Element Workplace.
You will see a list of all of the logical partitions. Define the range
of I/O priorities that will be used by each image, specifying the
minimum and maximum I/O priority numbers. It is recommended that you
use a range of eight values (for example 8 to 15), as this will correspond
to the number of values in the range that WLM uses. While it is not
enforced, it is assumed that you'll set the same range of I/O priorities
for all images in the same LPAR cluster. You can, however, prioritize
multiple LPAR clusters on the same CPC by setting different ranges
for each LPAR cluster.
If you have a partition running a system other than z/OS® (for instance z/VM®, z/TPF, z/VSE®) specify an appropriate default priority by setting the minimum and maximum to the same number. For example, if you have a z/VM partition running work that is equal in importance to the discretionary work in a z/OS partition, you could set the z/VM partition's range to 8–8, and the z/OS partition's range to 8–15.
If you have critical OLTP
applications running in a partition, on the other hand, you could
set the range for that partition to 15–15, and the z/OS partition's range to 7–14. In
this way, the OLTP work would always have a higher priority than the z/OS work. - In the Primary Support Element Workplace, click the Enable I/O Priority Queuing icon. You will see a simple panel that reads “Global input/output (I/O) priority queuing.” Click on the Enable box. Channel subsystem priority queuing is now enabled for the entire CPC.