18.3. Resource Controls

Resource controls, or rctls, is the mechanism used within OpenSolaris to configure limits for processes, tasks, projects, or zones. Resource controls are values set within the kernel and applied to the associated object at runtime, controlling the behavior of that object. Rctls have replaced most of the configuration that used to be done in the /etc/system file in earlier releases of Solaris. Using rctls enables dynamic management of the system's limits, instead of the static boot-time configuration provided by /etc/system. In addition, rctls are always used within the kernel instead of the traditional limits managed by the setrlimit system call. Although the setrlimit and getrlimit system calls, as well as the plimit command, are still available for backward compatibility, rctls are the preferred interface for managing system limits.