SAC System Maintenance and Troubleshooting 2 — Questions and Answers
Question 1: A server's RAID 5 array shows a degraded status after one disk failed. What is the correct immediate action?
- Rebuild the array immediately without replacing the disk
- Replace the failed disk and allow the array to rebuild (Correct answer)
- Shut down the server and restore from backup
- Convert the array to RAID 0 to improve performance
Correct answer: Replace the failed disk and allow the array to rebuild
In a degraded RAID 5 array, you should replace the failed disk as soon as possible and allow the controller to rebuild the array to restore redundancy.
Question 2: Which log file on a Linux system should you check first when diagnosing kernel-level hardware errors?
- /var/log/auth.log
- /var/log/syslog
- /var/log/dmesg (Correct answer)
- /var/log/apt/history.log
Correct answer: /var/log/dmesg
The /var/log/dmesg file contains kernel ring buffer messages including hardware detection and driver errors.
Question 3: A Windows system experiences a BSOD with error 'IRQL_NOT_LESS_OR_EQUAL'. What does this typically indicate?
- A corrupted user profile
- A driver accessing memory at an incorrect interrupt request level (Correct answer)
- A failed hard drive sector
- An expired software license
Correct answer: A driver accessing memory at an incorrect interrupt request level
IRQL_NOT_LESS_OR_EQUAL typically indicates a kernel-mode driver tried to access pageable memory at an interrupt request level that was too high.
Question 4: What is the purpose of running 'fsck' on a Linux filesystem?
- To defragment the filesystem for better performance
- To check and repair filesystem inconsistencies (Correct answer)
- To mount the filesystem in read-only mode
- To display current disk usage statistics
Correct answer: To check and repair filesystem inconsistencies
fsck (filesystem check) scans a Linux filesystem for errors and inconsistencies, optionally repairing them.
Question 5: A server's CPU utilization is consistently at 100%. Which command on Linux best helps identify the top consuming processes?
- netstat -an
- df -h
- top or htop (Correct answer)
- lsblk
Correct answer: top or htop
The 'top' or 'htop' commands display real-time CPU and memory usage per process, making them ideal for identifying runaway processes.
Question 6: During a scheduled maintenance window, you need to apply OS patches without losing unsaved work in running applications. What is the best approach?
- Apply patches during business hours to allow users to save their work
- Force reboot immediately after patching
- Notify users, allow them to save work, then patch and reboot during low-usage hours (Correct answer)
- Patch only the kernel and skip application updates
Correct answer: Notify users, allow them to save work, then patch and reboot during low-usage hours
Best practice is to notify users in advance, allow time for saving work, and schedule the reboot during a low-impact maintenance window.
Question 7: What does a high number of 'swap used' indicate on a Linux server?
- The CPU is overheating
- The system is running out of physical RAM and paging to disk (Correct answer)
- Disk I/O is performing optimally
- Network throughput is saturated
Correct answer: The system is running out of physical RAM and paging to disk
High swap usage means the system has exhausted physical RAM and is using slower disk-based swap space, which degrades performance.
SAC System Maintenance and Troubleshooting 2
A server's RAID 5 array shows a degraded status after one disk failed.
What is the correct immediate action?