Server migration service is considered as one of IaaS-typed cloud services. The target of the service is such a application that consists of servers and their clients, and, each server works on a computer called a working place (WP) and can voluntarily migrate to another WP if necessary. However, if the destination WP is full of servers, a server in the WP may be forced to be pushed out of the current WP and migrate to another WP to accept the voluntary immigration server. In this paper, in order to protect some particular servers from experiencing voluntary migration or forced migration much more than the other servers, in the viewpoint of migration fairness, three methods to determine the candidates to be pushed out based on the numbers of voluntary migrations and forced migrations. Next, we propose two methods to determine such one pushed-out server from the candidates that the impact caused by forced migration against the network becomes as small as possible.
