Exin Certified Data Centre Professional Exam Practice Test

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An optical fiber cable comes with the specifications 50/125 um.

What do the numbers represent?

A The first number represents the distance for a 10 Gb/s connection; the second number represents the distance for a 1 Gb/s connection.

B The first number represents the diameter of the core; the second number represents the diameter of the cladding in microns.

C The first number represents the diameter of the core; the second number represents the actual diameter cable including the buffer and jacket.

D The first number represents the required distance to single-phase power cabling; the second number represents the required distance to three-phase cabling.

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.

What is the primary reason to install a monitoring system in the data centre?

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

Which type of copper wire is used for grounding the racks to the SRG?

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

Which is the most damaging type of floor load?

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

What should be considered when implementing hot- or cold-aisle containment in an existing computer room?

A Equipment will get too hot at the rear (back) of the rack potentially resulting in more ICT hardware failures.

Answer : C

Hot- or cold-aisle containment is a strategy to improve the cooling efficiency and reduce the energy consumption of data centers by isolating the hot exhaust air from the cold supply air. However, implementing this strategy in an existing computer room may create potential issues with the existing fire suppression system(s), such as:

* The containment barriers may interfere with the distribution and activation of the fire suppression agents, such as water, gas, or aerosol, and reduce their effectiveness in extinguishing a fire.

* The containment barriers may create pockets of high temperature and pressure that could damage the equipment or the containment structure itself in the event of a fire.

* The containment barriers may obstruct the access and visibility of the fire detection and alarm devices, such as smoke detectors, heat sensors, or manual call points, and delay the response time of the fire suppression system(s).

* The containment barriers may violate the local fire codes and regulations that specify the minimum clearance and ventilation requirements for the data center.

Therefore, when implementing hot- or cold-aisle containment in an existing computer room, it is important to consider the impact on the existing fire suppression system(s) and take appropriate measures to ensure the safety and compliance of the data center, such as:

* Consulting with the fire authorities and the fire suppression system vendor to assess the compatibility and suitability of the containment solution with the existing fire suppression system(s).

* Modifying or upgrading the existing fire suppression system(s) to accommodate the containment solution, such as relocating or adding fire suppression devices, adjusting the discharge rate and pressure, or installing a secondary fire suppression system within the contained area.

* Installing fire-rated containment barriers that can withstand high temperatures and resist the spread of fire and smoke, and that have self-closing or automatic release mechanisms in case of a fire.

* Installing fire detection and alarm devices within the contained area and ensuring their proper integration and communication with the existing fire suppression system(s).

* Conducting regular testing and maintenance of the fire suppression system(s) and the containment solution to ensure their functionality and reliability.

How many monitoring points should be used in Temperature Measurement?