Exin Certified Data Centre Professional Exam Practice Test

Answer : C

Data centres are essential for supporting the IT operations and applications of various businesses across different industries. Data centre downtime can have a negative impact on the business results, such as loss of revenue, customer satisfaction, productivity, reputation, and competitive advantage. According to a web search, the average cost of data centre downtime in 2020 was $8,851 per minute, and the average duration of a data centre outage was 95 minutes1. This means that a typical data centre outage could cost a business over $840,000 in direct and indirect losses1. Therefore, data centre downtime can have a significant impact on the business results, regardless of the industry or sector.

Answer : B

Optical fiber cables are composed of a core, a cladding, and a coating. The core is the central part of the fiber that carries the light signal. The cladding is the layer surrounding the core that reflects the light back into the core and prevents signal loss. The coating is the protective layer that covers the cladding and provides mechanical strength and environmental protection. The specifications of an optical fiber cable indicate the dimensions of the core and the cladding in microns (m), which are one millionth of a meter. For example, a 50/125 m cable has a core diameter of 50 m and a cladding diameter of 125 m. The coating diameter is usually 250 m, but it is not part of the specifications.

Answer : A

The primary reason to install a monitoring system in the data centre is to notice abnormalities early so that actions can be taken to avoid disasters, according to the CDCP Preparation Guide1 and various web sources234. A monitoring system is a system that collects and analyzes data about the power, cooling, environmental, and security conditions in the data centre, and alerts the operators or managers about any issues or threats that may affect the performance, availability, or reliability of the data centre. A monitoring system can help to prevent or minimize the impact of disasters, such as power outages, fire, water damage, overheating, equipment failure, or cyberattacks, by providing timely and accurate information that enables fast and corrective action. A monitoring system can also help to improve the energy efficiency, capacity planning, and asset management of the data centre, by providing useful insights and trends that support informed decision making.

1: CDCP Preparation Guide, page 21, section 2.3.5 2: Improving Data Center Management and Monitoring5, page 1, section 1 3: Guide to Data Center Monitoring6, page 1, section 1 4: Why Data Center Monitoring is Essential7, page 1, section 1

Answer : C

The type of copper wire that is used for grounding the racks to the SRG (signal reference grid) in a data centre is braided copper wire or flat copper strip, according to the CDCP Preparation Guide1 and various web sources234. Braided copper wire or flat copper strip are preferred over thin or thick copper cable for grounding purposes, because they have lower impedance and higher surface area, which allow better dissipation of electrical noise and interference. Moreover, braided copper wire or flat copper strip are more flexible and durable than copper cable, which make them easier to install and maintain. Braided copper wire or flat copper strip should be connected to the SRG using exothermic welding or other code-compliant methods, and should follow the relevant standards and codes, such as ANSI/TIA/EIA-607 and NFPA 70.

1: CDCP Preparation Guide, page 23, section 2.4.2 2: Signal Reference Grid | Enterprise Data Center Design and Methodology5, page 1, section 1 3: Grounding System Ground Rod Stacking Installation - Rain Bird6, page 1, section 1 4: SmartRack Copper Bus Grounding Bar - Eaton Website7, page 1, section 1

Answer : C

The most damaging type of floor load for raised floor tiles in a data centre is the rolling load (RL), according to the CDCP Preparation Guide1 and various web sources234. A rolling load is the load that is applied by a moving object, such as a pallet jack, a forklift, or a rack on wheels. A rolling load can cause more stress and fatigue on the raised floor tiles than a static load, such as a concentrated load (CP) or a uniformly distributed load (UDL), because it creates dynamic forces and impacts that can crack, dent, or deform the tiles. Moreover, a rolling load can also damage the pedestals and stringers that support the tiles, and cause the tiles to become loose or misaligned. Therefore, when designing and installing a raised floor system, it is important to consider the maximum rolling load that the tiles can withstand, and to use appropriate materials and methods to enhance the strength and durability of the tiles. For example, some possible solutions include using steel or concrete-filled tiles, reinforcing the edges and corners of the tiles, and using locking or gravity-held systems to secure the tiles.

1: CDCP Preparation Guide, page 23, section 2.4.2 2: Top 5 Considerations - Selecting a Data Center Raised Floor Tile5, page 1, section 1 3: Raised Floor Systems: Explained, Improved and Reinvented6, page 1, section 1 4: Raised Floor Systems: Common Problems and Solutions7, page 1, section 1

Answer : B

The requirement of Concurrently Maintainability becomes relevant starting from Rated-3, according to the Uptime Institute Tier Classification System1. Concurrently Maintainability means that any component or system in the data centre can be maintained or replaced without affecting the availability of the IT equipment. This requires having redundant capacity components and multiple independent distribution paths serving the IT equipment. Rated-3 data centres are designed to achieve Concurrently Maintainability and have a minimum uptime of 99.982%. Rated-4 data centres also have Concurrently Maintainability, but they also have Fault Tolerance, which means that they can withstand any single unplanned event without affecting the availability of the IT equipment. Rated-4 data centres have a minimum uptime of 99.995%. Rated-1 and Rated-2 data centres do not have Concurrently Maintainability, as they have only one distribution path serving the IT equipment and no redundant capacity components. Rated-1 data centres have a minimum uptime of 99.671% and Rated-2 data centres have a minimum uptime of 99.741%.

1: Uptime Institute Tier Classification System2, page 1, section 1 2: Data Center Tiers Classification Explained: (Tier 1, 2, 3, 4)3, page 1, section 1 3: Data Center Tier Standards4, page 1, section 1

Answer : A

Sprinkler heads used in computer rooms activate at 57 C (135 F), which is the standard temperature rating for ordinary sprinklers. This is the temperature at which the heat-sensitive element of the sprinkler head, such as a glass bulb or a fusible link, breaks or melts, allowing water to flow from the sprinkler. Sprinkler heads are designed to activate only when exposed to a fire, not to ambient temperature fluctuations. Therefore, sprinkler heads should be installed at a sufficient distance from the heat sources, such as servers, racks, or ducts, to avoid accidental activation. Sprinkler heads should also be selected and installed in accordance with the relevant standards and codes, such as NFPA 13 and NFPA 75.

1: CDCP Preparation Guide, page 24, section 2.4.3 2: Sprinkler Systems in Data Centers3, page 1, section 1 4: Data Center Fire Protection5, page 1, section 2 6: Data Center Sprinkler System Design7, page 1, section 1