Which Eviction Policy threshold triggers aggressive connection reaping?
I'm getting mixed messages about what triggers connection reaping behavior on the BIG-IP. Is it utilization passing the high-water mark or the low-water mark? K15821 says that the trigger is passing the high-water mark, K15740 says that the trigger is passing the low-water mark (F5 training materials also say the trigger is passing the low-water mark).
From K15821: Overview of eviction policies:
Trigger
The High Water and Low Water thresholds configured in an eviction policy trigger when the adaptive connection reaping behavior starts and stops.
- High Water: Specifies the percentage of the quota for this context before flow eviction starts (defaults to 95 percent).
- Low Water: Specifies the percentage of the quota for this context before flow eviction ends, and processing of new flows resumes, after the high water mark is reached (defaults to 85 percent).
From K15740: Overview of adaptive connection reaping (11.6.0 and later):
Within an eviction policy, the high-water and low-water thresholds specify the resource quota percentage used to trigger when the adaptive connection reaping behavior starts and stops.
- High-water: Specifies the target maximum load on the context. The adaptive reaper becomes more aggressive as this limit is approached. The allowable range is 50 to 100, and the high-water value must be higher than or equal to the low-water value.
- Low-water: Specifies the aggressive sweeper activation threshold as a percentage of total capacity. The allowable range is 50 to 100, and the low-water value must be lower than or equal to the high-water value.
K156740 has been updated more recently than K15821, so it's possible that there has been a change in behavior between v13 and v14, and this is reflected in the dissonance between K15821 and K156740 (not that the 14.0 of 14.1 release notes say anything).