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Drive activity every 5 seconds

Western Digital Drives - The Preferred Drives of FreeNAS and TrueNAS CORE

chravis

Member
Joined
Jan 27, 2019
Messages
70
Greetings! I've had my first FreeNAS box up and running for a few weeks now. It's running on a Dell T30 with 2 WD Red drives mirrored. Everything seems to be working as expected. I ran all the drive tests and such before I started loading data.

I noticed, however, that every 5 seconds there is some kind of drive activity going on. The Dell T30 has a Drive Status Indicator light on the front panel that lights up each time. I can also hear it, which is how I noticed it to begin with. So, every 5 seconds there is a 1 second drive activity of some sort. What I'm wondering is is this normal? This may not be related to FreeNAS at all, I'm not sure. I'm pretty new when it comes to always-on computers.

Does anyone have any ideas?
 

melloa

Dedicated Sage
Joined
May 22, 2016
Messages
1,726
my first FreeNAS box up and running for a few weeks now
Welcome to the forum. My NAS don't show disk activity when is idle. The indication you see might be from the boot disk, so to be sure, could you please elaborate a little bit more on your configuration, so the members can provide more thoughts? Are the drives connected to the motherboard sata ports? What is the boot drive and where is it connected to? CPU/Memory, etc, as per forum requirements.
 

chravis

Member
Joined
Jan 27, 2019
Messages
70
Thanks @melloa. I have updated my signature to include my system specs because you're right, I didn't follow the forum rules and I apologize. Is this enough information for you?
 

melloa

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Joined
May 22, 2016
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1,726
Thanks @melloa. I have updated my signature to include my system specs because you're right, I didn't follow the forum rules and I apologize. Is this enough information for you?
That's fine :)

My experience is that there is no activity on my disks activity if the NAS is in idle (and it happens a lot as I'm the only user for it). Enable netdata on services and check disk activities. That will give you an idea what disk is the one in use. I'm not sure the USB boot would show at your Dell activity (I'd assume it won't). ada0 shown below is my boot disk ...

1561921610144.png
 

tfran1990

Senior Member
Joined
Oct 18, 2017
Messages
286
That's fine :)

My experience is that there is no activity on my disks activity if the NAS is in idle (and it happens a lot as I'm the only user for it). Enable netdata on services and check disk activities. That will give you an idea what disk is the one in use. I'm not sure the USB boot would show at your Dell activity (I'd assume it won't). ada0 shown below is my boot disk ...
wow i just looked at netdata for the first time on a test system of mine, its CRAZY in terms of detail.
@chravis take a look.
 

chravis

Member
Joined
Jan 27, 2019
Messages
70
Yes I turned it on. Crazy details. I had no idea that was there. Unfortunately just before my original post I started a large ftp transfer so I need to wait until that's over.
 

chravis

Member
Joined
Jan 27, 2019
Messages
70
Ok I've definitely got something going on but I'm not sure how to use the tools as my disposal to figure out what it is. This looks the same on both ada0 and ada1. My boot drives show no activity.

Screenshot (1).png
 

chravis

Member
Joined
Jan 27, 2019
Messages
70

Redcoat

Dedicated Sage
Joined
Feb 18, 2014
Messages
1,927
The drives on both my FreeNAS boxes show the same behavior - short writes every 5-6 seconds or so. Have done so for a long time. I think I was earlier convinced that this was to be expected if the System Dataset is on the pool as mine is, but I no longer recall the details.
 

Mihalich

Senior Member
Joined
Mar 14, 2017
Messages
283
My boot device

ada0.png
 

colmconn

Member
Joined
Jul 28, 2015
Messages
174
The activity at 5sec intervals is the flushing of ZFS TXGs to the underlying storage media and is perfectly normal behavior. With respect to tuning, some more info can be found here. I wouldn't go messing with the variables mentioned on that page, though unless you absloutely need to. If your system is otherwise quiescent, much of that activity will be driven by the system dataset (logs, data for graphs, etc.)

@Mihalich I hope your boot device is not a USB flash drive as all that write activity will shorten it's life.
 

chravis

Member
Joined
Jan 27, 2019
Messages
70
Thank you, @colmconn, for the explanation. This leads me to two questions:
1) does this have any impact on the life of a drive?
2) how come others in this thread have reported no similar activity on their disks?
I certainly don't want to go about changing system settings. I like things as vanilla as possible. I have searched through and found some threads about how it's not a great idea to have your discs cycled up and down. It's better to be spinning 24/7. So here's a newbie question - is an "idle" disk the same as a "cycled down" disk? Or, can I somehow get rid of this constant disk activity without cycling down the disks? Or better yet, should I just ignore this activity and assume all is well and get on with my life (even though it bugs me and others don't seem to have the same thing going on)?
 
Last edited:

Mihalich

Senior Member
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Mar 14, 2017
Messages
283

colmconn

Member
Joined
Jul 28, 2015
Messages
174
1. I doubt the drives even break a sweat.
2. I don't know. I can only tell you of my experience. I initially had my system dataset on my main pool but the noise of the drives irritated me. So I bought a couple of SSDs created a mirrored pool for VMs, jails and system dataset. The SSDs are naturally silent compared the the HDDs. I don't bother spinning my drives down. They're WD Reds (12 of them in 2 6-drive VDEVs) and their designed for continuous operation under heavier workloads than I demand of them. You cant get rid of the constant disk activity but you can move it else where to a more silent storage medium as I did. An idle disk is one that's not reading or writing anything (the definition of not necessarily written in stone) but is spinning and ready to read and write upon receiving a command. A spun down disk, by definition can't read or write anything from the disk and has to spin up before it can answer read/write queries.

The activity is part of the system. If the noise of the disk access if irritating you as it did me you could get a SSD (or a pair) for your system dataset, jails, etc. I had to sleep in the same room as it, that's why it bugged the hell out of me. But I didn't mind the bearly audible sound of spinning disks but the clicking was tortuous. Having said that everybody's got different thresholds for this stuff.
 

chravis

Member
Joined
Jan 27, 2019
Messages
70
Thank you everyone for the responses. @colmconn, you sound just like me. The sound drives me crazy. However, if I throw any more money at this machine for SSD drives then I'll be in the dog house, so I think I'll just leave it as is (for now). Now I know it's normal and isn't breaking anything and that's what I wanted to know in the first place. Thanks! This community is awesome!
 

bubski

Neophyte
Joined
Jan 26, 2020
Messages
6
Hello everybody

I observed the same kind of behavior in my newly built (and first) NAS.

FreeNAS-11.2-U7
Supermicro X8DTI-F
2 x Intel(R) Xeon(R) CPU L5640 @ 2.27GHz (24 cores)
88 GB ECC RAM
6 x 4 TB HDD RAIDZ2 via SATA
1 x 128 GB SSD via USB (BOOT)


I could hear the 6 HDDs doing something all the time every 5 seconds, so started looking for answers, and landed in this thread.

I read these very promising suggestions about moving the Jails to a separate, SDD pool. I decided to try that out, but in a VirtualBox first.
But after trying that out, I'm even more confused than before.

The VM I created in my MacBook:
FreeNAS-11.2-U7
1 x 32 GB IDE ada0 (BOOT)
1 x 128 GB SATA ada1 (ada1Pool)
1 x 128 GB SATA ada2 (ada2Pool)


And already after a clean setup (I don't know how cleaner it can get), with no Jails or plugins running, I can see the same activity pattern.
Interestingly, only on ada1Pool.
ada2Pool and the boot drive are virtually idle.

1.png

2.png


What's more interesting, is that if I export ada1Pool, this activity jumps over to ada2Pool.
And if I import ada1Pool back, the activity remains on ada2Pool.

3.png


And lastly, even though no Jails are running in this install, I tried going to the Jails page, and changing the pool under Activated Pool for Jail Manager. This seemed to have no effect.

Have you managed to sort your situation out @chravis?
 

chravis

Member
Joined
Jan 27, 2019
Messages
70
@bubski - My interpretation of the comments on this thread was that the noise I was hearing was just FreeNAS doing what it's supposed to do. The suggestion to switch to SSDs wasn't to prevent the activity, but to make it less audible. I didn't feel like putting in that effort, so I have learned to ignore the noise I hear every 5 seconds.
 

bubski

Neophyte
Joined
Jan 26, 2020
Messages
6
Thanks for responding @chravis, and yes, my interpretation was the same.
I was following @colmconn's lead who said:
The activity is part of the system. If the noise of the disk access if irritating you as it did me you could get a SSD (or a pair) for your system dataset, jails, etc.
But I don't think this is correct, because the VM setup I have, doesn't have any jails running, and this weird activity is still there.

Also, if this is just ZFS doing some kinda typical background maintenance or what not, I don't understand why I can see it happening in ada1Pool but not in ada2Pool. They are both empty.
 

jon_2112

Member
Joined
Feb 8, 2016
Messages
51
I've noticed the same thing since replacing my very quiet WD Red drives with 7200 rpm Toshiba X300s. I'm on 11.3, from which netdata has been removed. Interested in any updates to this.
 

bubski

Neophyte
Joined
Jan 26, 2020
Messages
6
I think I've got a lead. I went to System / System Dataset and for some reason, the System Dataset Pool was set to ada2Pool.
I opened the drop-down, and there were three options:
- freenas-boot (This must be ada0, right?)
- ada1Pool
- ada2Pool

So I picked freenas-boot, hit Save, and sure enough, ada2 is now idle and doesn't show that activity anymore (and unsurprisingly ada1 is idle too).
I expected ada0 to start showing the same pattern, but it doesn't.. No idea why.
 
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