CMDB Data Management and Data Quality Assurance

Configuration management database - much more than just a database. Even more powerful in conjuction with the CSDM framework

The ServiceNow Configuration Management Database (CMDB) stands as the cornerstone of efficient IT operations, serving as a unified repository for all configuration items (CIs). Beyond a mere database, the CMDB is a dynamic hub housing crucial data on hardware, software, services, applications and beyond. Its significance reverberates across various IT processes, ranging from IT Service Management to Operations and Asset Management. Acting as a single source of truth, the CMDB empowers organizations to streamline workflows, enhance service delivery, and maintain a comprehensive overview of their IT landscape.

In conjunction with the CMDB, the Common Service Data Model (CSDM) is as a vital framework, providing guidelines for service modeling within the CMDB. By aligning configuration items (CIs) and services with the organization's business strategy, CSDM facilitates standardization, integration, and the application of a common approach. This framework not only fosters consistency but also enables informed decision-making across various IT functions, including strategy development, planning, troubleshooting, and change execution.

Multisource CMDB - Overcoming Data Discrepancies

Multisource CMDB introduces a new layer of complexity to configuration management, particularly concerning the integration of multiple discovery systems as well as other data sources. Often, these disparate systems may identify the same devices in different ways, leading to inconsistencies and data quality issues within your CMDB.

Divergent naming conventions, varied data formats, and conflicting information can exacerbate the challenge of maintaining accurate and reliable CI data. These discrepancies not only undermine the integrity of the CMDB but also hinder effective decision-making, service delivery and your reports. To mitigate these challenges, ServiceNow has introduced the Identification and Reconciliation Engine (IRE engine). This sophisticated mechanism acts as a linchpin, harmonizing data from diverse sources and resolving conflicts through predefined identification and reconciliation processes. By leveraging IRE, we can avoid duplicates and ensure only the master sources can update particular CIs or concrete attributes of the CIs.

CMDB Identification rules - Avoid duplicates

Picture a scenario where multiple servers share identical names – a recipe for confusion and data integrity risks. CMDB identification rules serve as guardians against such chaos, mandating that each CI possesses a distinct identifier, be it a serial number, MAC address, or another distinguishing attribute.

1. Let's take the example above and further analyze. ServiceNow employs a series of identification rules to ensure each server within the CMDB is uniquely identified and accurately represented. Firstly, the system prioritizes the use of serial numbers as the primary identifier for servers. When server data is imported or discovered, ServiceNow checks for a match based on the serial number provided. If a match is found, indicating that the server already exists within the CMDB, the system will identify the CI and perform an update action instead of creating a new server.
2. However, if no match is found based on the serial number, ServiceNow proceeds to the next identification rule. In this case, the system attempts to match the server based on its name. Server names provide another level of identification, albeit with potential limitations such as naming conventions or changes over time. If a match is found based on the server name, the CI will be identified and updated.
3. If no match has been found based on the name of the server, the system will proceed and try to identify the server based on its mac address and name.
4. Finally, if no CI has been identified with all identification rules, a new configuration item will be created.

As you can see this robust mechanism ensures data integrity and helps to avoid duplicate entries within your CMDB.

Reconciliation Rules - Maintain high-quality data

While ServiceNow Discovery excels in capturing data on hardware and network devices, specialized asset discovery tools may offer deeper insights into software inventories or other aspects. However, the convergence of data from diverse sources poses challenges, particularly when different sources attempt to update the same records within the CMDB.

This complexity necessitates effective management to avoid discrepancies that could impact your data accuracy and data-quality. ServiceNow addresses this challenge through its Reconciliation Engine. Establish reconciliation rules assigning priority to each data source and specific attributes. By identifying a single source of truth for each configuration item and attribute, you will suceed and ensure your CMDB support your organization to make informed decisions and maintain a reliable data.

Consider a scenario where data from BMC Discovery, ServiceNow Discovery, and manual data loads from an Excel file on top of that contribute information about servers. Each of these sources may provide valuable insights, yet discrepancies in attribute values might pop-up, such as RAM and OS Version for example. For instance, BMC Discovery might report a server's RAM as 16 GB, while ServiceNow Discovery records it as 16384 MB. Similarly, the OS Version attribute may vary between sources due to formatting differences or update frequencies. To address these discrepancies, reconciliation rules play a pivotal role.

By defining source priorities for each attribute, CMDB admins can establish a hierarchy that governs which data source takes precedence. In this example, ServiceNow Discovery may be assigned the highest priority (100) for both RAM and OS Version, followed by BMC Discovery with a priority of 200, and manual data loads with a priority of 300. Through this structured approach, ServiceNow's Reconciliation Engine ensures that conflicts are resolved systematically, enabling you to maintain data accuracy and consistency within the CMDB. This proactive management strengthens the integrity of your data.

CI Class Manager - One place to configure the IRE rules

The CI Class Manager stands out as a central hub offering a comprehensive suite of tools for managing configuration item (CI) classes. With the CI Class Manager, you can view, create, or modify basic class definitions and settings tailored to your needs. This includes configuring the above mentioned identification and reconciliation parameters, as well as fine-tuning CMDB Health settings. Accessing the CI Class Manager is straightforward; you can navigate to it via the All > Configuration > CI Class Manager menu.

This intuitive interface is easy to use and will allow you to configure your Identification and Reconciliation rules within minutes. ServiceNow comes with a set of predefined identification rules for the major CI classes and it is suggested to not change them, unless you really have a reason. The reconciliation rules must be explicitly configured after identifing the authoritative data sources.

In summary, ServiceNow offers a robust suite of tools and functionalities to facilitate efficient configuration management for your IT. From the Configuration Management Database (CMDB) serving as a single source of truth to the utilization of the Common Service Data Model (CSDM) framework for standardized service modeling, ServiceNow empowers you to streamline workflows, enhance service delivery, and maintain data accuracy. Multisource CMDB capabilities, supported by the Identification and Reconciliation Engine (IRE), enable us to integrate data from diverse sources while mitigating data quality issues. ServiceNow's Reconciliation Engine ensures data consistency by comparing values across different sources, while the CI Class Manager provides a centralized interface for configuring CI classes and related settings. With ServiceNow's comprehensive suite of tools and functionalities, IT organizations can effectively govern their IT infrastructure, make informed decisions, and optimize operational efficiency by having a central CMDB managed in their ServiceNow instance.