A method is applied to a system including a host cluster and at least one pair of storage arrays. The host cluster includes a quorum host, which includes a quorum unit. The quorum host is an application host having a quorum function. A pair of storage arrays includes a first storage array and a second storage array. The quorum host receives a quorum request, temporarily stops delivering a service to the first storage array and the second storage array, determines, from the first storage array and the second storage array, which is a quorum winning storage array and which is a quorum losing storage array according to logic judgment, stops the service with the quorum losing storage array, sends quorum winning information to the quorum winning storage array, and resumes the delivered service between the host cluster and the quorum winning storage array.