Constant disk activity under idle?

TrueNAS General
1

Some time ago I posted about unexpected disk activity while nothing was actually happening. It was mostly blown off as general logging and such, but it turns out it was constantly logging errors to netdata because of permissions related to the onboard SATA DOM (which is not being used but truenas still sees it)

Well thought that was all fixed and done with, but now I am seeing consistent activity on both the OS nvme drive and on my disk drives. Pretty consistent activity on the nvme that I can’t figure out why, and activity roughly (but not consistently?) every 10ish minutes on the storage drive.

Running the latest v25.10.3. My system dataset is the storage drives, and it is 2x16TB in a mirror

Screenshot 2026-05-05 at 11.20.15 AM
Screenshot 2026-05-05 at 11.20.15 AM2848×1498 211 KB

2

What is running on your server? Is this only shared storage or do you have VMs and Apps? There isn’t enough information to go on. Where do you have your System Dataset pool? System, Advanced, the look for Storage box.

3

The system dataset is on my main storage pool (not the nvme). That’s the one detail I DID provide! haha

No VMs/Apps. Just myself home usage.

SMB + UPS services running

4

A guess is it might be the system polling SMART data on the drives, at least for some activity. UPS might be it. I don’t have UPS so I can’t check. Maybe try turning off UPS and see if stopping the monitoring helps?

Nothing in those graphs looks odd when compared to all the systems we see. Watching logs may be the only thing you could do since you caught the SATA DOM issue that way

5

Have you disabled SMB to see if that is related?

6

I haven’t just yet - but yes good point SMB and UPS are at least easy enough to temporarily disable and monitor without true impact during testing

7

I have no idea if those are the problem, but it was a easy thing to at least isolate. Best of luck locating the gremlins.

8

Well I disabled both services and decided to just let it restart to avoid anything still running

No change. Worse though, now I look at it again today and the Storage disks are basically identical, but the nvme has even more constant writing now - averaging 177 KiB/s

and this is with it… doing nothing and nothing connected to it!

9

The UPS service is still currently turned off/not running, but the USB cable is still connected. But now /var/log/messages is being constantly flooded with this:

May 8 17:03:54 truenas kernel: usb 3-4.3: USB disconnect, device number 121

May 8 17:03:57 truenas kernel: usb 3-4.3: new low-speed USB device number 122 using xhci_hcd

May 8 17:03:57 truenas kernel: usb 3-4.3: New USB device found, idVendor=0764, idProduct=0501, bcdDevice= 0.01

May 8 17:03:57 truenas kernel: usb 3-4.3: New USB device strings: Mfr=3, Product=1, SerialNumber=0

May 8 17:03:57 truenas kernel: usb 3-4.3: Product: ST Series

May 8 17:03:57 truenas kernel: usb 3-4.3: Manufacturer: CPS

May 8 17:03:57 truenas kernel: hid-generic 0003:0764:0501.3EEF: hiddev2,hidraw4: USB HID v1.10 Device [CPS ST Series] on usb-0000:00:14.0-4.3/input0

May 8 17:04:05 truenas kernel: usb 3-4.3: USB disconnect, device number 122

May 8 17:04:07 truenas kernel: usb 3-4.3: new low-speed USB device number 123 using xhci_hcd

May 8 17:04:08 truenas kernel: usb 3-4.3: New USB device found, idVendor=0764, idProduct=0501, bcdDevice= 0.01

May 8 17:04:08 truenas kernel: usb 3-4.3: New USB device strings: Mfr=3, Product=1, SerialNumber=0

May 8 17:04:08 truenas kernel: usb 3-4.3: Product: ST Series

May 8 17:04:08 truenas kernel: usb 3-4.3: Manufacturer: CPS

May 8 17:04:08 truenas kernel: hid-generic 0003:0764:0501.3EF0: hiddev2,hidraw4: USB HID v1.10 Device [CPS ST Series] on usb-0000:00:14.0-4.3/input0

May 8 17:04:15 truenas kernel: usb 3-4.3: USB disconnect, device number 123

May 8 17:04:18 truenas kernel: usb 3-4.3: new low-speed USB device number 124 using xhci_hcd

May 8 17:04:18 truenas kernel: usb 3-4.3: New USB device found, idVendor=0764, idProduct=0501, bcdDevice= 0.01

May 8 17:04:18 truenas kernel: usb 3-4.3: New USB device strings: Mfr=3, Product=1, SerialNumber=0

May 8 17:04:18 truenas kernel: usb 3-4.3: Product: ST Series

May 8 17:04:18 truenas kernel: usb 3-4.3: Manufacturer: CPS

May 8 17:04:18 truenas kernel: hid-generic 0003:0764:0501.3EF1: hiddev2,hidraw4: USB HID v1.10 Device [CPS ST Series] on usb-0000:00:14.0-4.3/input0

May 8 17:04:26 truenas kernel: usb 3-4.3: USB disconnect, device number 124

why would the device seemingly be constantly detected and then disconnected?