Patent attributes
A fault-tolerant data storage system associates durability requirements of service level agreements (SLAs) for volumes stored in the fault-tolerant data storage system with volume partitions stored in the fault-tolerant data storage system. For a given volume partition, volume data is stored in two or more replicas on two or more different system components and/or erasure encoded across multiple other system components. The fault-tolerant data storage system uses the respective durability requirements of the SLAs and failure statistics of the system components to allocate bandwidth for replacing lost instances of redundantly stored volume data such that the lost data is replaced within a target time calculated to guarantee the durability requirements of the SLAs are satisfied.