Some embodiments provide a novel method of performing health monitoring for resources associated with a global server load balancing (GSLB) system. This system is implemented by several domain name system (DNS) servers that perform DNS services for resources located at several geographically separate sites. The method identifies several different groupings of the resources. It then assigns the health monitoring of the different resource groups to different DNS servers. The method then configures each particular DNS server (1) to send health monitoring messages to the particular group of resources assigned to the particular DNS server, (2) to generate data by analyzing responses to the sent health monitoring messages, and (3) to distribute the generated data to the other DNS servers. The method in some embodiments is performed by a set of one or more controllers.