CompTIA Linux+ XK0-006 (V8) Practice Question

The correct answer is 'Slow remote storage response'. The key indicator in the top output is the wa (I/O wait) value, which is at 32.1%. This metric shows the percentage of time the CPU was idle while waiting for an I/O operation to complete. A high I/O wait time strongly suggests that the bottleneck is the storage subsystem, as processes are being delayed waiting for data from a disk. Since databases often rely on network-attached storage, a slow remote storage response is a very common cause for this symptom.

Incorrect answers:

• 'CPU bottleneck' is incorrect because the user space (us) and system (sy) percentages are low, and the idle (id) percentage is high. This indicates the CPU itself is not overworked.
• 'Out of memory' is incorrect. While low memory can lead to swapping (which is a form of I/O), the primary symptom of an out-of-memory condition would be visible in memory/swap usage statistics or through OOM killer activity in system logs. The high wa value points more directly to a storage issue than a memory issue.
• 'High context switching' is incorrect because it is a separate symptom that is not directly represented in the provided CPU statistics. While high I/O might lead to more context switches as the scheduler puts processes to sleep and wakes others, the root cause indicated by the high wa value is slow I/O, not the switching itself.