怎么样修改 HA 主备模式 自动切换资源啊? HA通过定义三种策略来选择资源组的切换和接管模式: Startup policy defines on which node the resource group will be activated when a node joins the cluster and the resource group is not active on any node. Fallover policy defines to which node the resource group will fall over when the resource group must leave the node where it is currently online due to a failure condition (or if you stop the cluster services on a node using the fallover option). Fallback policy defines to which node the resource group will fall back when a node joins and the resource group is already active on another node.