I have detected an issue about item in cache on one node :
Node 1:
active docs resident : < 1% !
replica doc resident : 20%
Node 2:
active docs resident : 16%
replica doc resident : <1%
Node 3:
active docs resident : 20%
replica doc resident : 14%
For RAM usage:
Total Allocated: 37.5 GB
Total in Cluster: 37.5 GB
In Use: 19 GB
Unused: 18.5 GB