This topic describes the major hardware and software components in the Enterprise Storage Management environment and describes the two different network management connections you can use to manage storage subsystems.
The management of your storage subsystems occurs over the network. The following are the major hardware components connected to the network. For a detailed description of the network setup requirements, refer to the storage management software installation guide.
Hardware Component |
Description |
Storage Management Station |
The computer you use to manage the storage subsystems on your network. |
Network Management Station (Optional) |
A Network Management Station (NMS) is a console with installed SNMP-compliant network management software that receives and processes information about managed network devices in a form that is supported by the Management Information Base (MIB) it uses. The Enterprise Management software provides information about critical storage subsystem events, using SNMP trap messages |
BOOTP or BOOTP-Compliant DHCP Server |
A BOOTP or BOOTP-Compliant DHCP Server is used to assign the network-specific information such as IP address and host name for each controller. This server is not required if you are going to manage all of your storage subsystems using the Host-Agent. |
Host |
A computer running one or more applications that accesses the storage subsystem over the I/O path. |
Storage Subsystem |
A storage entity managed by the storage management software. A storage subsystem consists of a collection of both physical components (such as drives, controllers, fans, and power supplies) and logical components (such as arrays and logical drives). A storage subsystem can span multiple physical enclosures. |
File Server (Optional) |
The storage management software can optionally be stored on a central file server. Management Stations on the network can then access the storage management software remotely. |
The storage management software is comprised of three major pieces:
The Client Management piece of the storage management software has two main windows: the Enterprise Management Window and the Subsystem Management Window.
The Enterprise Management Window is the first window that appears when you start the software. You use the Enterprise Management Window to add and discover the storage subsystems you want to manage and to provide a comprehensive view of all storage subsystems in your management domain. A list of storage subsystems that should be included in the management domain is stored in a local configuration file. After you have added the storage subsystems, you primarily use the Enterprise Management Window for coarse-level monitoring and alert notification of non-optimal storage subsystems. You also use it as the home base for launching an Subsystem Management Window for a particular storage subsystem. All storage subsystem-specific management tasks are provided in the Subsystem Management Window.
You use the Subsystem Management Window to manage (configure, maintain, and recover) the physical components (controllers, drives, and fans for example) and logical components (logical drives and arrays) that comprise a storage subsystem. The Subsystem Management Window is specific to an individual storage subsystem. Therefore, you can only manage a single storage subsystem within an Subsystem Management Window. However, you can launch other Subsystem Management Windows to manage other storage subsystems.
The Host-Agent management software is an optional piece of software that you can install on one or more hosts that are connected to the storage subsystems. The Host-Agent, along with the Ethernet connection on the host, provides you with another network management connection to the storage subsystem (see Host-Agent Managed Storage Subsystem's description, below) rather than using the individual Ethernet connections on each controller in the storage subsystem (see Directly Managed Storage Subsystem's description, below).
Your storage management station can communicate with a storage subsystem through the host that has Host-Agent management software installed. The Host-Agent takes requests from the storage management station through the Ethernet connection to the host and sends them to the controllers in the storage subsystem through the I/O connections between the host and storage subsystem.
A multi-path driver can also be called an I/O path fail-over driver. There is typically a redundant pair of active controllers in a storage subsystem. When you create a logical drive in the storage subsystem, one of the controllers is automatically or manually chosen to "own" the logical drive and control the I/O between the logical drive and the application host along the I/O path.
When a component along the I/O path to a controller or the controller itself fails, ownership of the logical drives that had been assigned to that controller will automatically transfer to the other controller in the pair. The multi-path driver manages this failover process.
Types of Network Management Connections
The storage management software manages all storage subsystems over the network. However, the software allows you to configure two different types of network management connections into a storage subsystem: a direct connection or a host-agent connection.
For increased connectivity, you can manage a storage subsystem using any combination of network management connections (direct only, host-agent only, or multiple host-agents). A direct and host-agent combination is also allowed but is not a recommended configuration because you would be using three Ethernet connections (one to each controller and one through the host). When you configure more than one network management connection into a storage subsystem, the storage management software is aware of each connection and automatically chooses a connection when you attempt to manage the storage subsystem by launching an Subsystem Management Window. If a particular connection is currently not responding, the software tries all other configured network management connections into that storage subsystem.
The controllers in the storage subsystem are managed directly over the network through each controller's Ethernet connection on the storage subsystem. To manage the storage subsystem through these Ethernet connections, you must define each controller's IP address (or optionally, each controller's host name) and attach a cable to the Ethernet connections on the storage subsystem. You can then use the Enterprise Management software to include the storage subsystem in the management domain.
The controllers in the storage subsystem are managed through an Ethernet connection on a host instead of using the Ethernet connections on each controller. The Host-Agent software on the host, described above, facilitates communication between the management station and the controllers in the storage subsystem. To manage a storage subsystem using this method, you must install the Host-Agent software on the host and then use the Enterprise Management software to include the host in the management domain (by including the host in the domain, you will also be including any attached Host-Agent Managed hosts).