Why is my NAS drive clicking?

Not all clicking is bad, but some clicking is a genuine emergency, and the difference is the pattern and whether errors accompany it.

Normal clicks

Hard drives make quiet, occasional clicks and ticks as the heads seek and park. A soft click when the drive idles or spins down, or intermittent ticking during heavy access, is ordinary mechanical operation: nothing to worry about, especially if SMART is clean and the array is healthy.

Warning clicks

Be concerned when the clicking is loud, repetitive or rhythmic: the classic "click of death", particularly if it comes with:

• Read/write errors or slow performance.
• The drive dropping out of the array intermittently.
• The drive failing to spin up or not being detected.
• Rising Reallocated or Current Pending Sector counts.

That pattern suggests the head assembly is struggling: a failing drive.

What to do

1. Back up now if you can still read the data.
2. Check SMART data and run an extended test; correlate the noise with errors.
3. If the clicking tracks with errors or drop-outs, replace the drive: do not wait for it to fail completely, especially in a degraded array.

The table lists CMR NAS drives for a replacement.