As applications become more complex, and the level of concurrency in systems continue to rise, developers are struggling to scale complex data models on top of a traditional byte stream interface. Middleware tailored for specific data models is a common approach to dealing with these challenges, but middleware commonly reproduces scalable services already present in many distributed file systems. We present DataMods, an abstraction over existing services found in large-scale storage systems that allows middleware to take advantage of existing, highly tuned services. Specifically, DataMods provides an abstraction for extending storage system services in order to implement native, domain-specific data models and interfaces throughout the storage hierarchy.