There are a few of my customer still running vSphere 5.1 U1 and one of them reported an issue related to the VMFS Heap Size (VMFS3.MaxHeapSizeMB) configuration a few days ago. Keep in mind that my customer upgraded to U1 from a previous vSphere 5.1 version meaning that the old VMFS3.MaxHeapSizeMBÂ was retained at 80 MB …