This might be possible with some customization but this is not our preferred way. Instead, we can store selected indices in duplicate or more copies inside a clustered database. In this way, all servers can have their own disk. Each key of each index will belong to one partition but each partition will have more than one physical copy, each on a different server. The cluster query logic will perform the load balancing. On the update side, the cluster will automatically do a distributed transaction with two phase commit to keep the duplicates in sync.