System

A system consists of one or more I/O groups. Each I/O group contains two nodes. In enclosure-based systems, a control enclosure is an I/O group.

I/O group
The pair of nodes within a single enclosure is known as an input/output (I/O) group.
Quorum
A quorum device is used to break a tie when a SAN fault occurs, when exactly half of the nodes that were previously a member of the system are present. A quorum device is also used to store a backup copy of important system configuration data.
System topology
The system topology can be set up in following ways.
System layers
The system layer affects how the system interacts with another system and other external systems that run IBM® Storage Virtualize software.
Licensed functions
The base license that is provided with your system includes the use of its basic functions. However, there are also extra licenses that can be purchased to expand the capabilities of your system. Administrators are responsible for purchasing extra licenses and configuring the systems within the license agreement, which includes configuring the settings of each licensed function on the system.
Bitmap space configuration
As part of Copy Services, the system supports policy-based replication. If you are currently using relationships to replicate data between systems, you may need to reallocate bitmap space to use policy-based replication.
Throttles
Throttles are a mechanism to control the amount of resources that are used when the system is processing I/Os on supported objects. The system supports throttles on hosts, host clusters, volumes, copy offload operations, and storage pools. If a throttle limit is defined, the system either processes the I/O for that object, or delays the processing of the I/O to free resources for more critical I/O operations.

Parent topic: Concepts