LFAREA calculation example 4
Table 1 shows a series of LFAREA requests on a z/OS® system with 64 GB of online real storage at IPL. The 1 MB pages are requested with target and minimum percentages of 40% and 20%, respectively, while the 2 GB pages are requested as a target numerical value that is increased with each request. This illustrates how the 1 MB pages are reduced toward the minimum to satisfy the requested target number of 2 GB pages. Table 1 also shows that as the number of 2 GB pages reaches 19, the required reduction in 1 MB pages would be below the requested minimum. In this case, the system prompts to re-specify LFAREA. Also shown is a case where the requested number of 2 GB pages is 25, which by itself exceeds the 80% system limit and results in a prompt to re-specify LFAREA.
LFAREA request with 64 GB of online real storage available at IPL | Resulting number of 1 MB pages | Resulting number of 2 GB pages |
---|---|---|
LFAREA=(1M=(40%,20%),2G=11 | 24576 (40%) | 11 |
LFAREA=(1M=(40%,20%),2G=12 | 24576 (40%) | 12 |
LFAREA=(1M=(40%,20%),2G=13 | 22118 (36%) | 13 |
LFAREA=(1M=(40%,20%),2G=14 | 20275 (33%) | 14 |
LFAREA=(1M=(40%,20%),2G=15 | 18432 (30%) | 15 |
LFAREA=(1M=(40%,20%),2G=16 | 15974 (26%) | 16 |
LFAREA=(1M=(40%,20%),2G=17 | 14131 (23%) | 17 |
LFAREA=(1M=(40%,20%),2G=18 | 12288 (20%) | 18 |
LFAREA=(1M=(40%,20%),2G=19 | Unable to satisfy 1 MB minimum | Unable to satisfy 1 MB minimum |
LFAREA=(1M=(40%,20%),2G=25 | Above 80% limit | Above 80% limit |