Hi,
Just coming back to update on this issue.
After a few changes in the ClearPass VM config, the server has been up and running for the last 3 days without crashing!
When we first redeployed the OVF file to create the ClearPass VM, the vCPU configuration was set to 24 by default. We upgraded the ESXi from 5.5 to 6.0. Just after deployment, vmware tools was outdated and VM hadware compatibility was ESXi 5.0 or later (VM version 8).
But our ClearPass servers have 2 processor sockets with 6 cores each, which gives us 12 physical cores. The servers also have Hyper Threading enable, whick makes the 12 physical cores look like 24 logical processors to ESXi.
With vCPU set to 24, the servers crashes. It also crashes changing vCPU to 12 but leaving vmware tools and hardware compatibility outdated.
It seems that the only way the servers does not crach it to map one vCPU to one physical core, and upgrading vmware tools and hardware compatibility to the latest versions (ESXi 6.0 or later VM version 11), if you are using ESXi 6.0.
And, in my case, the vCPU setting has to be 12 virtual processors, with 1 core per socket, that is 12 virtual sockets, even if the physical host has 2 sockets with 6 cores each!
Setting vCPU to 12 with 6 cores per socket also resulted in crashing the server.
Thanks for all replies!