A system that implements a data storage service may store data on behalf of storage service clients. The system may maintain data in multiple replicas of partitions that are stored on respective computing nodes in the system. A master replica for a replica group may increment a membership version indicator for the group, and may propagate metadata (including the membership version indicator) indicating a membership change for the group to other members of the group. Propagating the metadata may include sending a log record containing the metadata to the other replicas to be appended to their respective logs. Once the membership change becomes durable, it may be committed. A replica attempting to become the master of a replica group may determine that another replica in the group has observed a more recent membership version, in which case logs may be synchronized or snipped, or the attempt may be abandoned.