Phasor measurement units (PMUs) are rapidly being installed across the USA as part of the DOE Smart Grid Investment Grant (SGIG) programs. Within three years there are expected to be over 1000 PMUs installed by nine SGIG grantees. However, there will be many more installed in distribution networks to help accommodate intermittent power from rooftop solar and electric vehicles. Additionally, PMUs will begin appearing at the terminals of generation equipment, transformers, and large motors. We predict they will be used in large commercial and residential facilities. Several of the SGIG grantees intend to install highly available redundant measurement systems. One of the key reasons for redundancy is to support the requirements to be able to make security patches to the software without losing data. These software patches must be made with no loss of data. The Entergy company experience during the Hurricane Gustav power island event is a clear example of the value of PMUs for real time operations of the grid. We show in this paper how fully redundant cyber secure systems can be assembled using standard PMUs and standard commercial software.