New Opportunities for PODC?: Massive, Volatile, but Highly Predictable Resources
Classical models for distributed systems focus on fine-grained resources and failures (e.g. single processes and fail-stop or byzantine). Cheap hardware, the rise of the worldwide web, and now the rise of cloud computing has transformed distributed systems practice. Instead of single resources, application sites have ten-thousands of virtual machines, and in addition to independent failures, there are a raft of correlated failure modes.
 Motivated by the reality the computing is the fastest growing consumer of electric power (and associated carbon emissions), we are creating new model for cloud computing systems, Zero-carbon Cloud, that taps a growing phenomenon of "stranded power" -- energy that is generated, but has no economic value. Stranded power is significant today (7.7 terawatt-hours in the Midwest power grid in 2014, perhaps 50 TWH worldwide), and growing rapidly as concerns about climate change drive a conversion of the grid to intermittent renewable energy generation such as wind and solar.
 Zero-carbon cloud resources have several novel properties. First, they have correlated availability at massive scale -- 10K-1M cores in an entire data center will go on or offline at once. Second, these periods may be highly predictable -- external factors such as weather, predicted load, and power markets shape the availability of stranded power. Third, these properties can be engineered -- for example, a small amount of energy storage can be used to "delay" unavailability. We will propose Zero-carbon cloud, or massive volatile resources based on stranded power as an interesting new model for a variety of classical distributed systems challenges (consistency, etc.) and new challenges for optimization.
 More information is available at http://zccloud.cs.uchicago.edu/