A extremely bizarre situation. I’m brand new to TrueNAS setting up v25.04.2.4 yesterday. I created a RAIDZ1 pool with 4x HDDs and successfully copied across about 7.5TB to the pool fine vis SMB. However I wasn’t happy with a particular user’s Home Directory being at the top of the file directory, so I edited the location in the user’s settings and everything went wrong.
Long story short. At this point the HDD activity went flat-out and I tried various ways to stop the activity, but nothing worked, so I decided to reinstall TrueNAS.
However when I went into the BIOS boot menu I noticed the HDDs where still making activity noises which was weird. So I unplugged the SATA to each drive and found 3 of the 4 drives having activity with no physical data connection!
How is this even possible, after all I’ve had these 4 drives for years and they’ve been fine right up until it hit the button to change the Home Directory.
I suspected maybe it’s S.M.A.R.T. running but it wasn’t due to start for 2 days and surely it wouldn’t default to run on multiple drives at the same time.
As you already mentioned, it may be related to internal diagnostics or initialization processes, which can produce audible noise.
However, if it goes on indefinitely; or for a quite long duration, it may be taken as an early sign that those drives are preparing themselves for an ascension.
If so; it may be the best time to start backing up your data…!
Yes if it was 1 drive I’d agree, definitely.
2 drives maybe.
But 3 drives behaving in an autonomous way, all at literally exactly the same moment is no coincidence. Something has triggered the behaviour. What’s more the S.M.A.R.T. test results on all 4 drives when installed in my QNAP NAS last month showed them in perfect health.
I’m going to leave the drives spun up over the weekend and run a long S.M.A.R.T. test to see if anything arises.
TLDR: It seems it was indeed somehow related to the S.M.A.R.T feature causing the constant drive activity, bearing in mind my TrueNAS was a fresh install (so a S.M.A.R.T task never executed, as far as I know).
@smione I have ordered a new PSU due later this week, just in case, thanks for the suggestion. I did try powering on just 1 disk at a time without a SATA cable connected and the 3 drives still produced constant activity.
@winnielinnie The 4 drives are Hitachi Deskstar HDS723030xxxxxx, 7200RPM, 3TB. Interestingly they have different firmware versions with:
SDA (HDS723030ALA640) running version MKAOA800, had phantom activity
SDB (HDS723030ALA640) running version MKAOA3B0, had phantom activity
SDD (HDS723030ALA640) running version MKAOA3B0, had phantom activity
SDC (HDS723030BLE640) running version MX6OAAB0, had no phantom activity
The drives were always spun-up, but I knew they were actively seeking as I could audibly hear the arm/head operating constantly from 3 of the 4 disks, even though the MB HDD LED did not illuminate and TrueNAS showed no corresponding activity (ignoring System Dataset Pool writes).
The long version of what happened since. On Friday night I reconnected the 4 drives to motherboard and ran a manual S.M.A.R.T. “Long” test on all 3 problem drives, presto!! within 30 seconds the constant drive chatter stopped on all drives! I installed Scrutiny and all drive S.M.A.R.T. results were fine as expected. However around 10 hours later drive SDA was constantly active again, so I ran another manual S.M.A.R.T. test and the activity stopped. I left TrueNAS running for about 30 hours (I also had stopped Scrutiny at this point as it caused disk activity every 30 seconds) and the disks are still behaving as of writing this.
I still don’t understand why TrueNAS is putting the drives into some erratic state of constant activity inadvertently via S.M.A.R.T. functions. Potentially it could be solved long-term by a firmware update (as SDC running assumingly newer firmware had no issues) but I don’t seem to be able to find the firmware online. Or maybe these drives just aren’t greatly compatible with TrueNAS? Like I said previously, they did work fine for years in my QNAP NAS.
Some HDDs perform internal maintenance tasks such as “SMART offline data collection”, “background media scan (BMS)”, or “servo calibration” whenever they have power but are idle.
These operations can cause noticeable activity (head movements, vibrations, or clicking sounds) even if the drive is not connected to a host system.
The model “Hitachi/HGST Deskstar 7K3000 (HDS723030ALA640)” seems to support SMART “Execute Off-line Data Collection” according to the official specification manual pdf. link
That means it’s quite possible your drive is running one of these autonomous background routines when powered on.
So the observed disk activity, even with only the power cable attached and no SATA link, seems to me like “normal firmware behavior” rather than a fault or host-initiated operation.
A bit off-topic, but your comment about possibly updating the HDD firmware got me curious as well — I’d really like to know which HDD models actually allow this, and what software or tools are needed to do it.
