论文标题
基于领导者的复制存储中的数据新鲜度
Data Freshness in Leader-Based Replicated Storage
论文作者
论文摘要
基于领导者的数据复制通过对领导者节点的顺序写入提高了高度可用的分布式存储系统的一致性。领导者完成写作后，追随者节点是由多播机制写成的，只能保证最终保持一致。以信息年龄为单位（AOI）作为新鲜度度量，我们表征了领导者的数量如何影响通过瞬时读取查询检索到的数据的新鲜度。特别是，我们为领导者写作时间的确定性模型和追随者写作时间的概率模型得出了读取查询的平均年龄。我们获得了指数分布的追随者写作时间的平均年龄的封闭式表达式。我们的数值结果表明，取决于写操作与两个节点的相对速度，存在最佳的领导者数量，可最大程度地降低检索到的数据的平均年龄，并且随着领导者写作的相对速度的增加，该数量会增加。
Leader-based data replication improves consistency in highly available distributed storage systems via sequential writes to the leader nodes. After a write has been committed by the leaders, follower nodes are written by a multicast mechanism and are only guaranteed to be eventually consistent. With Age of Information (AoI) as the freshness metric, we characterize how the number of leaders affects the freshness of the data retrieved by an instantaneous read query. In particular, we derive the average age of a read query for a deterministic model for the leader writing time and a probabilistic model for the follower writing time. We obtain a closed-form expression for the average age for exponentially distributed follower writing time. Our numerical results show that, depending on the relative speed of the write operation to the two groups of nodes, there exists an optimal number of leaders which minimizes the average age of the retrieved data, and that this number increases as the relative speed of writing on leaders increases.
