Data storage method, data recovery method, and relevant device and system

The invention discloses a data storage method for improving the storage consistency of a distributed memory system in an embodiment. The method comprises: a major storage node performs EC coding on a data fragment to be stored to obtain a target EC stripe; (m+k) target storage nodes for storing (m+k) target EC blocks of the target EC stripe are determined in a storage node group; a preparation message is sent to the target storage nodes; a response sent by each target storage node is received; and after the response messages of all the target storage nodes are received, an execution message is sent to the target storage nodes to instruct the target storage nodes to write in the target EC blocs in a preparation log. The embodiment of the invention further provides a data recovery method and a relevant device.