A method and system is provided for maintaining customer data in a data store system utilizing a scalable partitioning framework. More specifically, the data store of a customer service system is partitioned (divided) into multiple partitions by a partitionable key of customer data so that each partition owns a subset of the customer data. By maintaining several partitions that store a subset of the customer data exclusive to each other, blackout or brownout problems can be local to one partition and, thus, the availability for the entire system will be increased. Moreover, a set of partitionable keys, a minimal unit to be moved between partitions, is grouped and associated with a partition. By eliminating direct dependencies between the partitions and the partitionable keys, the system can have great flexibility with regard to migrating customer data between partitions and adding a new partition.