Troubleshooting Questions
Practice questions for Troubleshooting topic in CompTIA Linux+. 22 questions covering this domain.
An administrator runs `top` and observes that many processes are in state `D` (uninterruptible sleep) and the system load average is 15 on a 4-CPU sys...
An administrator needs to identify which process is causing the highest disk I/O on a server in real time. Which tool provides per-process disk I/O st...
An administrator runs `df -h` and sees the root filesystem at 100% capacity, but `du -sh /*` shows only about 60% usage. What is the MOST likely expla...
An administrator suspects a server is using excessive swap space. Which command displays the current memory and swap usage in a concise, human-readabl...
Which command directly reads the kernel ring buffer and is used to view hardware detection messages and kernel errors, particularly useful immediately...
An administrator suspects high CPU usage on a server. Which interactive command provides a real-time, auto-updating view of running processes sorted b...
A RHEL 9 server cannot resolve hostnames. `/etc/resolv.conf` is configured correctly. Which command tests whether the DNS server is responding to quer...
An administrator finds that Apache cannot write to `/var/log/myapp/` even though the directory permissions are `rwxrwxrwx`. `ls -lZ` shows the directo...
An administrator needs to list all currently listening TCP ports along with the process name and PID of each listening service. Which command provides...
A mount operation fails with the error "wrong fs type, bad option, bad superblock on /dev/sdb1." The device is not currently mounted. Which command ch...
An administrator needs to review the active nftables ruleset to troubleshoot a firewall issue on a system using nftables as the firewall backend. Whic...
An administrator runs `vmstat 1 10` and observes that the `wa` (I/O wait) column consistently shows values between 35–50%. What does this indicate, an...
An administrator needs to trace all system calls made by a running process with PID 5678 to diagnose why it is failing silently without producing log ...
Which command traces the network path from the local system to a destination host, showing each router hop and its round-trip latency?
An administrator stops a container named `analytics` using Podman because it is consuming excessive CPU. Which Podman command immediately sends SIGKIL...
An administrator reviews memory usage with `free -m` and sees low `free` but high `buff/cache` and a large `available` value. What does this indicate?
An administrator is investigating high network latency between two servers and wants real-time statistics on packet loss and latency for each network ...
A server has a high number of zombie processes (state `Z`) accumulating over time. What is the correct approach to resolve zombie processes?
An administrator needs to identify which directories are consuming the most disk space under `/var`. Which command shows disk usage summarized per sub...
An administrator suspects that SELinux is blocking a service's access to a port. Which command searches the audit log specifically for recent SELinux ...
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