The
vSphere 4.1 API Reference document in incorrect with respect to these performance counters. The VMware documentation team has fixed most of these entries in the current release of the
vSphere 5.1 API reference document. However, the counters listed below are still stated as available for the ESXi/ESX 4.x release, which is incorrect:
Counters at the host level
memory.swapunreserved.average
Counters at the virtual machine level cpu.idle.summation
network.droppedRx.summation
network.droppedTx.summation
Performance data for the unavailable counters is not included in vCenter Server statistics collection from hosts and is, therefore, not available from vCenter Server or the vCenter Server database. Because the counters listed above do not exist in the ESXi/ESX 4.x release, users cannot pull historical and/or real time data for these counters from vCenter Server and/or a direct host connection using the vSphere Client.
Alternative representations of the following unavailable performance counters is available from hosts using esxtop (an SSH session to the ESX/ESXi host) or resxtop (using VMware Command Line Interface to connect to an ESX/ESXi host).