Recovery synchronization in a distributed storage system

摘要

A method for data storage includes sending write commands to a first storage node, for storing data in a data volume on the first storage node. In response to a decision to create a copy of the data volume on a second storage node, (i) the write commands are sent both to the first storage node and to the second storage node, and (ii) a snapshot of the data volume is created and sent from the first storage node to the second storage node. The copy of the data volume is created by the second storage node based on the snapshot and on one or more of the write commands received at the second storage node.

主权项

1. A method for data storage, comprising:
sending write commands to a first storage node, for storing data in a data volume on the first storage node; in response to a decision to create a copy of the data volume on a second storage node, (i) sending the write commands both to the first storage node and to the second storage node, and (ii) creating and sending from the first storage node to the second storage node a snapshot of the data volume, wherein the snapshot includes at least a write command having a specified serial number; creating the copy of the data volume by the second storage node, by receiving the snapshot and creating the copy of the data volume from the received snapshot and the write commands that are received at the second storage node and whose serial numbers are larger than the specified serial number; and sending from the second storage node to the first storage node a snapshot request that specifies the specified serial number, and discarding in the second storage node any received write commands whose serial numbers are smaller than or equal to the specified serial number.