A Case for Informed Service Placement on PlanetLab

We examine PlanetLab resource utilization data from the perspective of the designer of a resource discovery system. We are particularly interested in variability of, and correlations among, resource utilization attributes, both among nodes and over time. We find that, for some resources, the quantity available at a fixed time differs significantly across nodes, suggesting a potential benefit to using a resource discovery system to wisely place application instances. We further find that, for many nodes, resource availability varies over time, suggesting periodic migration of application instances could be useful. We find that some attributes are moderately correlated among nodes at the same site, but that on a single node, attributes are generally not correlated to one another. Finally, we find that for some node pairs, measured latency can reasonably predict available bandwidth based on a correlation function derived from observing latency and bandwidth across all node pairs.