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What CMDB benefits can we expect beyond a network management system?

An NMS provides real-time feedback about operations and performance. A CMDB maintains relationships between components of an environment. Should we have both?

We have 900 routers and switches and currently use network management tools, including SolarWinds. The only configuration...

management done is in a flimsy Microsoft Excel sheet. I need to convince senior management of the differences between what we have and a CMDB such as HP Enterprise Universal CMDB or BMC Atrium, and the benefits of CMDB with or instead of NMS.

While network management systems (NMSs) have been around since the early days of networking, configuration management databases (CMDBs) have recently grown in popularity. Many network and system administrators question the value of a CMDB and if they need to replace existing NMS investments with a CMDB.

An NMS provides tactical information and tools, somewhat akin to a car's speedometer. The speedometer tells the driver information about how fast the car is moving, but nothing about what is happening inside of the car to get it to that speed. CMDB benefits are different, not replacing an NMS. A CMDB is like a mechanic's tool: a schematic of the whole car and how the parts relate to each other.

A network management system monitors the enterprise's networks and alerts based on real-time conditions present. For example, an NMS may send an alert if a port reaches 80% utilization, or create an alert when a spanning tree error occurs. The NMS considers the health of whole systems and groups its monitors by device. Administrators can increase efficiency by applying the same monitoring templates to groups of devices. Some NMS systems even gather and store system configurations, or offer remote code execution as a management tool.

The CMDB's role is to express relationship information that administrators -- mechanics of the IT world -- use to assess the risk of an issue in one component, and how changes affect the overall system. In automotive terms, where the NMS provides a speed readout, the CMDB might relay how the transmission relates to the engine and the drive shaft, and how the drive shaft affects the differential, rear axle and tires. Essentially, a CMDB builds these relationships between different configuration items.

Configuration items are not bound to the traditional network device boundaries. A configuration item can be a single part of a device's configuration, e.g., the configuration of a single switch port, instead of the whole switch. CMDBs are not limited to network devices either; the CMDB's main benefit is that it relates all systems, applications and users to each other. IT operations management improves when admins understand how changes to one component ultimately affect several other components.

There are some conceptual overlaps between an NMS and a CMDB. They both deal with device configurations. An NMS will record configurations and document changes over time in the same way that it would track changes to a monitored port. A CMDB won't necessarily track the configuration on its own; it projects how changes to that configuration will affect other configuration items in the environment. NMS and CMDB also both include aspects of an inventory/asset management system.

CMDB benefits trump the manual spreadsheet

Another common IT inventory tool is the Excel worksheet, which your company currently uses. A proper CMDB can and should replace this and other primitive IT asset management systems. CMDB benefits over spreadsheet-based inventory management are numerous.

A CMDB is a relational database, which builds multiple relationships between items that a flat Excel file cannot. There is also a versioning and divergence aspect to the Excel versus CMDB argument: Engineers can pass around an Excel file, creating scenarios where different engineers work off of different versions, or worse, making updates in parallel that will require a data merge. A CMDB is centralized, allowing multiple engineers concurrent access and avoiding data integrity issues altogether.

The clear CMDB benefits over Excel files for configuration management show in input/output options as well. Data comes in and out of an Excel file primarily by human input, but a CMDB can be integrated with automation and orchestration tools, and enable data extraction to enhance reporting. Existing NMS tools can feed data into a CMDB, or the organization can use a CMDB to define monitors in the NMS.

CMDB is a key component in an ITIL-compliant approach to IT service management and IT operations management. Moreover, a good CMDB complements an NMS. Successful businesses with any amount of IT infrastructure will have both NMS and CMDB tools, and will not have flat spreadsheets of IT assets.

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