Modifying, or “overriding,” the value of a resource type’s static attribute applies the
change to all resources of the type. When a static attribute is overriden and the
configuration is “dumped” (saved), the main.cf file includes a line in the resource
definition for the static attribute and its overriden value.
attribute分五类，Res-specific 、type-dependent、 type-independent 、Global&local 、temp，type-dependent又分static和non-static,static值可以override。
