The present disclosure discloses an arbitration processing solution when brain split occurs in cluster. The solution includes: receiving, by the quorum storage apparatus, first master quorum node preemption requests within a first master quorum node preemption detection period sent by the at least two quorum nodes when brain split occurs in the cluster; sending, by the quorum storage apparatus, a first master quorum node preemption success response message to the initial master quorum node when the first master quorum node preemption request sent by the initial master quorum node is received; where the first master quorum node preemption success response message indicates the initial master quorum node succeeds in master quorum node preemption.