A systems administrator is performing a physical inspection of servers in a data center. While walking past a rack, the administrator hears a distinct, rhythmic clicking sound coming from one of the older database servers. This server utilizes a RAID 10 array of mechanical hard drives. A quick check of the server's management interface shows slightly elevated I/O wait times, but no drives are currently flagged as 'failed' by the RAID controller. Which of the following is the MOST likely cause of this sound?
The correct answer is a failing mechanical hard drive. The scenario describes a rhythmic clicking sound, often called the 'click of death,' which is a classic auditory symptom of a hard drive's read/write head assembly malfunctioning as it repeatedly tries and fails to find the correct track. This mechanical failure often precedes a formal error report from the drive's SMART monitoring or the RAID controller. The report of elevated I/O wait times also supports this diagnosis.
A malfunctioning cooling fan typically produces a whirring, grinding, or buzzing noise rather than a rhythmic click. A failed RAID cache battery does not produce an audible sound; its primary symptom is a significant decrease in write performance as the controller disables the write-back cache. A failing power supply might buzz, whine, or its fan might make a grinding noise, but it would not produce the specific, repetitive clicking of a struggling drive head.