Power Enterprise Pool

Power Enterprise Pool provides flexibility and value for Power Systems™. A Power enterprise pool is a group of systems that can share Mobile Capacity on Demand (CoD) processor resources and memory resources.

You can move Mobile CoD resource activations among the systems in a pool with Hardware Management Console (HMC) commands. These operations provide flexibility when you manage large workloads in a pool of systems and helps to rebalance the resources to respond to business needs. This feature is useful for providing continuous application availability during maintenance. Not only can the workloads be easily moved to alternate systems but the processor activations and memory activations can be moved. Disaster recovery planning also is more manageable with the ability to move activations where and when they are required.

Power Enterprise Pool configuration requirements

There are two different types of pools:

· The Power 770 and E870 pools

· The Power 780, 795, and E880 pools

The Power 770 and 780 systems require a minimum of 4 static processor activations. The Power 870 and 880 require a minimum of 8 static processor activations. The Power 795 requires a minimum of 24 static processor activations. 50% of memory must be active for all systems, and a minimum of 25% of the active memory must be static memory.

An HMC can manage multiple Power Enterprise Pools and can also manage systems that are not part of a Power Enterprise Pool. Systems can belong to only one Power enterprise pool at a time.

Master HMC and managing Hardware Management Consoles

The master HMC authorizes all Power enterprise pool change operations. It also performs all pool change operations for the servers that it manages. A managing HMC is an HMC that you have designated to the master HMC of a pool as a managing HMC for the pool. A managing HMC can be directed by the master HMC to perform pool change operations for the servers that are not managed by the master HMC.

You can perform the following tasks by using any managing HMC, including the master HMC:

· View pool information

· Add Mobile CoD resources to a server

· Remove Mobile CoD resources from a server

· Set a new master HMC for the pool

· Synchronize pool information

The following tasks must be performed on the HMC designated as the master HMC:

· Create pool

· Update pool (including updating the pool name)

· Recover pool

· Update the managing HMC list for the pool


Scale Out or Scale Up

Horizontal and vertical scaling

Methods of adding more resources for a particular application fall into two broad categories: horizontal and vertical scaling.[5]

  • To scale horizontally (or scale out/in) means to add more nodes to (or remove nodes from) a system, such as adding a new computer to a distributed software application. An example might involve scaling out from one Web server system to three. As computer prices have dropped and performance continues to increase, high-performance computing applications such as seismic analysis and biotechnology workloads have adopted low-cost "commodity" systems for tasks that once would have required supercomputers. System architects may configure hundreds of small computers in a cluster to obtain aggregate computing power that often exceeds that of computers based on a single traditional processor. The development of high-performance interconnects such as Gigabit Ethernet, InfiniBand and Myrinet further fueled this model. Such growth has led to demand for software that allows efficient management and maintenance of multiple nodes, as well as hardware such as shared data storage with much higher I/O performance. Size scalability is the maximum number of processors that a system can accommodate.[4]
  • To scale vertically (or scale up/down) means to add resources to (or remove resources from) a single node in a system, typically involving the addition of CPUs or memory to a single computer. Such vertical scaling of existing systems also enables them to use virtualization technology more effectively, as it provides more resources for the hosted set of operating system and application modules to share. Taking advantage of such resources can also be called "scaling up", such as expanding the number of Apache daemon processes currently running. Application scalability refers to the improved performance of running applications on a scaled-up version of the system.[4]

There are tradeoffs between the two models. Larger numbers of computers means increased management complexity, as well as a more complex programming model and issues such as throughput and latency between nodes; also, some applications do not lend themselves to a distributed computing model. In the past, the price difference between the two models has favored "scale up" computing for those applications that fit its paradigm, but recent advances in virtualization technology have blurred that advantage, since deploying a new virtual system over a hypervisor (where possible) is often less expensive than actually buying and installing a real one. Configuring an existing idle system has always been less expensive than buying, installing, and configuring a new one, regardless of the model.

Note, that NFV defines these terms differently: scaling out/in is the ability to scale by add/remove resource instances (e.g. virtual machine), whereas scaling up/down is the ability to scale by changing allocated resources (e.g. memory/CPU/storage capacity)[6]