In one of my project I have encountered a fatal error of Memory ballooning in Appserver when running a Load test.
There were 6 nodes of Appserver in our Application under test. When we performed couple of load test we observed, at only one of the six node CPU utilization is going up to 60-70% while at others it's apprx ~20%.
Initially we thought it could be load balancing issue, but when checked load were equal on each App nodes.
When we monitored the App server memory utilization we found Memory ballooning issue on that particular node, that node was getting high utilized and when it went sort of memory it was reclaiming memory from other servers on the VM network.
"Memory ballooning allows the host to borrow that unused memory and allocate it to the VMs with higher memory demand"
VM memory ballooning can create performance problems. To overcome the issue we disabled the Memory ballooning on the App server when running the load test.
Let me know if any help required to understand the issue
Memory Ballooning Issue on Web/App Server
Memory ballooning issue