Data reading method, device and system

The invention discloses a data reading method. A cluster data system comprises computing nodes and coordinating nodes, wherein shared caches shared by multiple computing nodes are arranged on the coordinating nodes, and a memory is arranged in each computing node. The data reading method comprises the steps that the computing nodes look up data pages to be read in the memories and send data obtaining requests to the coordinating nodes when the data pages to be read are not looked up, wherein the data obtaining requests are used for indicating the coordinating nodes to look up the data pages to be read from the shared caches; the computing nodes read the data pages to be read sent by the coordinating nodes, wherein the data pages to be read are sent to the computing nodes when the coordinating nodes look up the data pages to be read in the shared caches. By means of the data reading method, the quantity of SSDs in the cluster data system can be decreased and the utilization rate of the shared caches in the cluster data system can be improved while the data reading rate is ensured.