# Intelligent Monitoring of Data Center Physical Infrastructure
## 2 Data Center Physical Infrastructure  
The priorities of highly classified data centers are not only to maintain the highest level of reliability and availability of the operation, but also fast, specific event identification and energy consumption monitoring, which altogether improve the level of energy efficiency. Monitoring functions include technological components and their control, optimal energy support, alarm and event reporting, and further data reporting to the central control component. Data acquired from the distributed modules and components are then real-time data for central servers at the level of the main control. Event processing is difficult because the system's availability level must remain within the required limits. Event information must be accurate and timely so that the appropriate intervention measures can be triggered. During data center operation, many events take place, and these events must be filtered from actual alarms [9; 18]. Some events have other consequences as a result of a chain reaction. In order to successfully eliminate all the consequences, the causes of the problem should be found based on the appropriate philosophy of cause and effect and their filtering [17]. In the event of a component failure, all corrective measures must be taken to establish the previous state of process availability within the required time period. During active data center operation, there is no time available to manually perform an analysis of the cause or to determine the percentage chance that the event that actually occurred was the main cause of the error. A manual analysis approach always requires expertise [19]. An information center requires a high degree of availability of the system [20]. On the other hand, there must be a balance between the system availability requirements and energy efficiency, operating costs, and, in a later stage, maintenance costs. A well-known characterization of this is the classification of the levels of availability of data centers (Tier I to Tier IV) by the Uptime Institute [21]. The classification describes and differentiates data centers according to their degree of availability and represents the four levels of requirements to be taken into account [22; 23]. The development of standards for these requirements was provided by ANSI/TIA-942--the standard for telecommunications infrastructure for data centers issued by the Telecommunications Industry Association (TIA) [24]. In this series of standards, the data center class Tier I has non-redundant capacity components and non-redundant paths to distribute paths that serve the site's computer equipment. The data center has cooling of computer rooms and energy distribution. It can also have (or not) a UPS and/or an engine generator. The data center should be closed for annual scheduled maintenance work and repairs. Repair maintenance may require additional shutdowns. Mistakes or spontaneous faults in the infrastructure components will cause disturbances in the data center. Thus, for instance, a Tier I data center is suitable for small businesses where IT is dedicated to internal business processes. A Tier II data center has redundant performance components and individual non-redundant distribution channels that serve the computer equipment of a particular site. They have a UPS and generators, but a route redundancy plus one (\(N+1\)) is required. Maintenance of critical energy routes and other parts of the infrastructure of a particular place requires the shutdown of computer processes. A Tier II data center could be suitable for internet-based businesses without any serious financial penalties for service quality. A Tier III data center is maintenance-free and has excessive performance components and several distribution channels that serve the computer equipment of an individual part of the data center. In this case, the computer equipment uses only one distribution path at any time.