[VMware vSphere] NMP plugin solution

If you encounter hangs / disconnections from the network / inoperability of ESX version 4.0 servers when one or more LUNs are disconnected, then know that this is a problem in the NMP plugin.
This issue is discussed in more detail in the article:
virtualgeek.typepad.com/virtual_geek/2009/12/an-important-vsphere-4-storage-bug-and-workaround.html

easy way to fix the problem:
1. Update vCenter to version 4U1;
2. Update all nodes of all clusters to version 4U1;
3. Run the command “esxcfg-advcfg -s 1 / VMFS3 / FailVolumeOpenIfAPD” on ALL nodes of ONE of the clusters;
4. By connecting-disconnecting the test LUN, make sure that the problem is resolved;
5. In case of successful elimination of the problem on one cluster, apply the above setting on the nodes of the remaining clusters;