I was having some issues with my VPS instances (they would sometimes go down), so I looked for a monitoring system that would alert me when a VPS goes offline and also save statistical data. I initially looked at NodeQuery, but the problem with it was that it only updated every 5 minutes, so if a VPS became unavailable for 1-2 minutes, it barely noticed. I checked out other options too, but eventually settled on Observium.
Observium

