XK0-004 · Question #502
A systems administrator is investigating degraded server performance. The administrator executes diagnostic commands that result in the following output: Which of the following is the MOST likely…
The correct answer is C. Too many write operations are happening on the server, causing the IO to wait for requests to be. High iowait percentage in CPU statistics indicates processes are blocked waiting for I/O operations to complete, which is a primary cause of degraded server performance.
Question
A systems administrator is investigating degraded server performance. The administrator executes diagnostic commands that result in the following output:
Which of the following is the MOST likely cause of the degraded server performance?
Exhibit
Options
- AThe processes running in the background are causing high load averages
- BThe server has not been rebooted for 1,055 days causing old processes to utilize the CPU
- CToo many write operations are happening on the server, causing the IO to wait for requests to be
- DThe server has little free memory available and is not using any swap memory, causing slow
How the community answered
(42 responses)- A5% (2)
- B5% (2)
- C74% (31)
- D17% (7)
Why each option
High iowait percentage in CPU statistics indicates processes are blocked waiting for I/O operations to complete, which is a primary cause of degraded server performance.
High load averages are a symptom, not a root cause - they can result from CPU, memory, or I/O pressure, and the diagnostic output points specifically to I/O wait rather than CPU-bound background processes.
Server uptime does not inherently degrade performance; long uptime alone is not a cause of CPU or I/O issues unless combined with other factors like memory leaks.
The 'wa' (iowait) field in tools like top or vmstat shows the percentage of time the CPU is idle while waiting for I/O operations - high values directly indicate a storage or disk bottleneck. Excessive write operations can saturate disk throughput, causing a queue of pending I/O requests that forces processes to wait and drives up load averages. This pattern is the most specific and actionable explanation for degraded performance based on I/O-related diagnostic output.
The scenario describes low physical memory utilization and absence of swap usage, which contradicts the premise of memory exhaustion causing slowdowns.
Concept tested: Diagnosing high iowait CPU utilization on Linux servers
Source: https://man7.org/linux/man-pages/man1/top.1.html
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