It looks like you are experiencing low memory exhaustion. The kernel uses low memory to track allocations of all memory. When low memory is exhausted, it doesn't matter how much high memory is available, the oom-killer will begin killing processes to keep the server alive.
I suggest you check your host and guest memory usage and allocation in VSphere, and make sure it supports your guest systems. Chances are probably that you do not have enough physical RAM to perform the tasks, or do not have enough memory allocated to your virtual machine, or have a process in your guest system that causes memory starvation because it is not configured correctly, e.g. Oracle SGA.