Example of Workload Manager classes with memory limits
This example examines memory allocation to groups of processes with varying memory targets.
Three groups of processes must run: a group of interactive processes that need to run whenever they are used (PEOPLE), a batch job that always runs in the background (BATCH1), and a second, more important batch job, that runs every night (BATCH0).
PEOPLE has a specified memory minimum of 20%, a memory target of 50 shares, and a class tier value of 1. A 20% minimum limit ensures that the desktop applications in this class resume fairly quickly when users touch their keyboards.
BATCH1 has a memory minimum of 50%, a memory target of 50 shares, and a tier value of 3.
BATCH0 has a memory minimum of 80%, a memory target of 50 shares, and a tier value of 2.
Classes PEOPLE and BATCH1 have a total memory minimum limit of 70. Under normal operation (when BATCH0 is not running), both of these classes are allowed to get all of their reserved memory. They share the rest of the memory in the machine about half and half, even though they are in different tiers. At midnight when BATCH0 is started, the memory minimum total reaches 150. WLM ignores the minimum requirements for the lowest tiers until processes in the upper tiers exit. BATCH0 takes memory from the BATCH1 50% reserve, but not from the PEOPLE 20% reserve. After BATCH0 is done, memory reserves for tier 3 processes are honored again and the system returns to its normal memory balance.