Preface: The discrepancy doesn’t mean that your hdd is bad. It’s an input for decision making. I use this to spot “new new” drives vs “refurbished but sold as new” drives especially on amazon.

chatgpt generated image beware

I was extending my NAS disks and I had already got 2x 12TB Seagates from amazon.de. Since they have been behaving nicely for the last 6 months, I wanted to get 2 more. Then I saw a random review which mentions the farm logs showing different values than smart monitoring tools (s.m.a.r.t.) aka smartctl. I have never heard FARM logs before, apparently it stands for Field Accessible Reliability Metrics and useful additional metric for Seagate drives which is harder to reset than smart Power_On_Hours metric.

I researched on reddit and saw that there is a big market there: https://www.tomshardware.com/pc-components/hdds/german-seagate-customers-say-their-new-hard-drives-were-actually-used-resold-hdds-reportedly-used-for-tens-of-thousands-of-hours

However, noone is explaining the exact command to run. Here they are

sudo apt update
sudo apt install smartmontools 

# Usual smart logs for power on hours.
sudo smartctl -a  /dev/sdb | grep "Power_On_Hours"

# Only applicable for Seagate drives
# FARM Logs
sudo smartctl -l farm /dev/sdb | grep "Power on Hours"

If you drive is “new new”, you should get almost zero hours for both of these commands. However, in my case smartctl -a was giving almost zero but smartctl -l farm 28k hours which is totaling to ~1166 days. Obviously this doesn’t mean that the drive is bad or anything. Drive is manifactured probably around that time. However some refurbishing event happened and got it fixed and resold to me with clean S.M.A.R.T.