Hi everybody. I had a great talk with someone in Level 3 tech support who explained what’s going on.
Apparently the sound I’m hearing is PWL - “Preventive Wear Leveling”. It’s a periodic head sweep to distribute lubricant and prevent wear in a particular place if lubricant were to build up in one spot. On many older models, this would happen maybe once a minute. But on some builds it’s maybe every 5 seconds. My drives are WD4004FXWX 4TB Black drives.
Hope this helps.
