Scalable data storage techniques are described. In one or more implementations, data is obtained by one or more computing devices that describes fault domains in a storage hierarchy and available storage resources in a data storage pool. Operational characteristics are ascertained, by the one or more computing devices, of devices associated with the available storage resources within one or more levels of the storage hierarchy. Distribution of metadata is assigned by the one or more computing devices to one or more particular data storage devices within the data storage pool based on the described fault domains and the ascertained operational characteristics of devices within one or more levels of the storage hierarchy.