Who owns the address? A performant block storage model for hybrid cloud

Rapidly growing data volumes stimulate the migration of block storage from on-premise to hybrid cloud. Hybrid cloud block storage is composed of both on-premise and remote cloud storage. Unfortunately, the heterogeneity of on-premise clients (e.g., laptops, mobile devices, etc.) with various operating systems encumber the hybrid cloud architecture design. What's worse, the demanding fault-tolerance and latency requirements pose challenges to the block storage system. Under the premise of strong consistency and availability, there are two mainstream models of hybrid storage systems: the low latency but low throughput “active-standby” model where only one node can provide reads and writes, and the high throughput but high latency “active-active” model where all nodes can provide reads and writes. To address the dilemma between throughput and latency, we design a novel storage model called the “logical-active” model, which partitions the input data into shards in terms of the block address ranges and selects one owner node called “logical-active” for each shard. A unique “logical-active” node manages the creation and deletion of the shard and provides reads and writes for the clients, while one or more borrower nodes called “logical-standby” provide only reads after synchronization with the “logical-active” node. In this way, the “logical-active” model achieves low latency close to the “active-standby” model and high throughput close to the “active-active” model.