VMware Balloon Driver Causes Application Performance Issues in Guest VMs
If Vmware Tools are installed in the VM, then VMware’s Memory Balloon Driver does aggressive Memory Management for VMs on that ESXi Host. This might result in increased paging activity and even disk thrashing on that VM. This behavior is most commonly experienced with Oracle databases running within VMs.
An example of a situation occurs while running TPC-H tests with Oracle inside a Red Hat Linux VM ( in this case VM had 4 cores and 4 GB RAM, and VMware tools). This causes the TPC-H test to fail with ‘segmentation fault’ errors. This happens at even low Degree of Parallelism (=2) and generally little load.
You can tell if windows VM is swapping by looking at Pages Input/ Sec field (perfmon.exe > Memory > Pages Input / sec ) or the Page File % Used counter (perfmon.exe > Page File ).
In a Linux VM, you can monitor the Wait % for the process and/or monitor the swap space used using TOP command.
If you run into this situation, you can increase the Memory to the VM or disable the Ballooning Driver.
Below is a Vmware KB article with instructions on Disabling the Ballon Driver.
Below is a VMware KB article describing this issue with the VMware Balloon Driver.