Relationship to Other Solaris Resource Control Features

The Solaris operating environment includes several other features that provide control over certain kinds of resources. Some features, such as real-time scheduling, nice(1), quotas, and processor sets, are part of the basic Solaris system.

Solaris Bandwidth Manager is a co-packaged software package, dynamic system domains are features of the Sun Enterprise 10000 system platform, and dynamic reconfiguration is a feature of the Sun Enterprise system platform.

All of these components offer types of resource management, but each differs from Solaris Resource Manager capabilities in some way.

• Real-time Scheduling

  The standard Solaris operating system uses the TS scheduling class for most conventional work, but it also offers real-time (RT) scheduling to users with sufficient privilege. The RT scheduling class implements a very different (and intentionally very weighted) scheduling policy to ensure that specific workloads or processes get immediate access to the processor.

  Solaris Resource Manager can coexist on the same system as the RT scheduling class, but it will have no control over any process running in the RT class. The Solaris Resource Manager fair share scheduler is able to manage the CPU time resources of only those processes that are not running in the RT scheduling class. For example, on a four-processor system, a single-threaded process can consume one entire processor; in fact, this is precisely what happens if the requesting process is CPU-bound. If this system also runs Solaris Resource Manager, regular user processes will be competing for the three CPUs not already being used by the real-time process. (Note that the real-time process might not use the CPU continually. When it is idle, Solaris Resource Manager will utilize all four processors.)

• nice(1) Command

  The nice command permits a user to manipulate program execution priority. Unless superuser privilege is invoked, this command only permits the user to lower the priority. This can be a useful feature (for example, when a user starts a low-priority batch job from an interactive login session), but it relies on the cooperation of the user. Solaris Resource Manager enforces administrative policies, even without the cooperation of the user.

• Quotas

  Solaris file systems have quota mechanisms that enable the administrator to restrict the disk consumption of individual users. This functionality is independent of Solaris Resource Manager.

• Processor Sets

  Processor sets were introduced in Solaris 2.6. This feature permits the administrator to divide multiprocessor systems into logical groups and permits users to launch processes into those groups. The advantage is that workloads running in one processor set are protected from CPU activity taking place in any other processor set. In some ways, this is similar to what Solaris Resource Manager does, but the two features operate on a completely different basis. Processor sets control only CPU activity. The control is at a relatively broad hardware level, because processors can belong to only one processor set at a time. Especially in the case of relatively small systems, the granularity may be quite high: on a 4-processor system, the minimum resource that can be assigned is 25 percent of the system.

  Solaris Resource Manager has much finer-grained control; each user is allocated a share of the system. The shares can be distributed arbitrarily on a fine granularity, and the scheduler will allocate resources accordingly. For example, if 50 shares are granted and one user has 40 of them, that user will get 40 / 50 = 80 percent of the resource. Similarly, if 67 total shares are granted, a user with 57 shares will get 85 percent of the resource. In addition, Solaris Resource Manager can control resources other than CPU. See The Role and Effect of Processor Sets for more information on the interaction of Solaris Resource Manager and processor sets.

• Dynamic System Domains

  The Sun Enterprise 10000 has a feature called dynamic system domains, which permit the administrator to logically divide a single system rack into one or more independent systems, much like the partitioning features available on mainframes. Each system runs its own copy of Solaris. For example, a machine with 32 CPUs on 8 system boards might be operated as 1 system with 16 CPUs, and 2 other systems with 8 CPUs each. In this configuration, three copies of Solaris would be running. Dynamic system domains also provide tools that manage the transfer of resources into and out of each copy of Solaris, thus creating a relatively broad facility for managing physical resources. (The minimum unit of inter-domain allocation is an entire system board.)

  Solaris Resource Manager is similar to dynamic system domains in that it also provides the administrator with mechanisms to allocate resources, but it does so in very different ways. Solaris Resource Manager runs within a single instance of Solaris, and provides a finer degree of administrative control over the resources in that system. Solaris Resource Manager can be used to segment resources among many users and applications in each instance of Solaris within a Sun Enterprise 10000 system and used in conjunction with dynamic system domains.

• Dynamic Reconfiguration

  The dynamic reconfiguration feature of Sun Enterprise servers enables users to dynamically add and delete system boards, which contain hardware resources such as processors, memory, and I/O devices. The effect of a dynamic reconfiguration operation on memory has no impact on Solaris Resource Manager memory-limit checking.

• Solaris Bandwidth Manager

  Solaris Bandwidth Manager is an unbundled package that works with the Solaris kernel to enforce limits on the consumption of network bandwidth. Solaris Bandwidth Manager is a form of resource management software that applies to a different class of resources. Solaris Resource Manager and Solaris Bandwidth Manager have different and separate management domains: Solaris Resource Manager operates on a per-user or per-application basis, while Solaris Bandwidth Manager manages on a per-port, per-service, or per-protocol basis.