CDCP Data Center Operations and Maintenance 4 — Questions and Answers
Question 1: During a preventive maintenance window, a UPS battery string fails a capacity test at 78% of rated capacity. What is the recommended action?
- Continue monitoring and retest in 30 days
- Replace the entire battery string immediately (Correct answer)
- Replace only the failed cells and retest
- Reduce the load on that UPS by 22%
Correct answer: Replace the entire battery string immediately
A battery string failing below 80% of rated capacity is the standard threshold for immediate replacement to ensure reliable backup power.
Question 2: Which metric is most critical when evaluating the efficiency of a data center cooling system?
- Total cooling tonnage
- Supply air temperature setpoint
- Cooling system COP (Coefficient of Performance) (Correct answer)
- Number of CRAC units installed
Correct answer: Cooling system COP (Coefficient of Performance)
COP measures the ratio of cooling output to energy input, directly reflecting cooling system efficiency.
Question 3: A data center operations team is implementing a change to add a new PDU. Which document must be updated FIRST before energizing the new PDU?
- Incident log
- Single-line electrical diagram (Correct answer)
- Asset inventory spreadsheet
- Vendor maintenance contract
Correct answer: Single-line electrical diagram
The single-line electrical diagram must be updated first as it is the authoritative reference for safe electrical work and lockout/tagout procedures.
Question 4: What is the purpose of a 'hot aisle containment' strategy in data center operations?
- Reduce noise levels from server fans
- Prevent mixing of cold supply air with hot exhaust air (Correct answer)
- Lower the ambient temperature of the entire data hall
- Increase the airflow velocity to server intakes
Correct answer: Prevent mixing of cold supply air with hot exhaust air
Hot aisle containment captures server exhaust air directly and routes it to cooling units, preventing recirculation and improving cooling efficiency.
Question 5: A facility manager notices the PUE has risen from 1.45 to 1.68 over three months. What is the MOST likely cause to investigate first?
- Increased server utilization
- Cooling system inefficiency or failure (Correct answer)
- Addition of new IT equipment
- Lighting system upgrades
Correct answer: Cooling system inefficiency or failure
A rising PUE with stable IT load typically indicates cooling overhead has increased, pointing to cooling system degradation or misconfiguration.
Question 6: Which practice BEST supports 'lights-out' or remote operations in a data center?
- Increasing on-site staffing levels
- Deploying DCIM with remote monitoring and alerting (Correct answer)
- Installing additional physical security cameras
- Reducing the number of managed devices
Correct answer: Deploying DCIM with remote monitoring and alerting
DCIM (Data Center Infrastructure Management) provides real-time visibility, alerting, and remote control capabilities essential for lights-out operations.
Question 7: During a fire suppression system inspection, the clean agent cylinder weight is found to be 5% below the minimum fill level. What action should be taken?
- Document the finding and recheck in 6 months
- Refill the cylinder to full capacity before returning to service (Correct answer)
- Disable the suppression system until the next scheduled maintenance
- Increase the sensitivity of smoke detectors to compensate
Correct answer: Refill the cylinder to full capacity before returning to service
A cylinder below minimum fill level must be recharged before returning to service to ensure the system can deliver the required agent concentration.
CDCP Data Center Operations and Maintenance 4
During a preventive maintenance window, a UPS battery string fails a capacity test at 78% of rated capacity.
What is the recommended action?