vSphere 6, Clear state

Memory management in vSphere 5 happens with following 4 states.

High State: 100% of minFree available (<100% and >=64%, TPS is in action)
Soft State: 64% of minFree is available (<64% and >=32%, Ballooning is in action)
Hard State: 32% of minFree is available (<32% and >= 16%, Compression, Page Swapping)
Low State: 16% of minFree is available (<16%, Page Swapping)

ESXi 5.x Memory state chart

while in vSphere 6, this has changed, a new memory management state has been introduced called Clear state which is equivalent to previous High state. So now in ESXi 6 following are memory management states available.

High State: 300% of minFree available (<300% and >=64%, TPS is in action)
Clear State: 100% of minFree available (TPS is in action, this is previous version High State)
Soft State: 64% of minFree is available (<64% and >=32%, Ballooning is in action)
Hard State: 32% of minFree is available (<32% and >= 16%, Compression, Page Swapping)
Low State: 16% of minFree is available (<16%, Page Swapping)

ESXi 6 Memory states chart

In Short, an additional state which has been introduced called Clear state, and High State is tripled with compare to last version, now it’s 300% of minFree value of an esxi host, this is purely so TPS gets a chance to be triggered long before it hits Clear state and carry on acting on memory accordingly.

Reference: Duncan Epping’s blog about vSphere 6, Memory states & vSphere 6 Resource Management Guide

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