A block-based storage system may implement reducing durability state for a data volume. A determination may be made that storage node replicating write requests for a data volume is unavailable. In response, subsequent write requests may be processed according to a reduced durability state for the data volume such that replication for the data volume may be disabled for the storage node. Write requests may then be completed at a fewer number of storage nodes prior to acknowledging the write request as complete. Durability state for the data volume may be increase in various embodiments. A storage node may be identified and replication operations may be performed to synchronize the current data volume at the storage node with a replica of the data volume maintained at the identified storage node.