Ubuntu - Constant disc access - SOLVED

The disc-access light seems to be on continuously despite disconnecting the network and not running any s/w. If I run System Monitor, it shows all processes to be sleeping (except for SysMon of course).
I can understand some background, automatic defragmenting (does Ubuntu do that?) but that must finish eventually.
It’s not a big problem (I hope) but I’m curious. Any ideas?

Might be worth firing up “Disk Utility” and checking the drives SMART status.

Is this started recently, or has the PC always done this?

How old is the HDD ?

Laptop or Desktop … has the PC received any knocks whilst switched on recently ?

Are we talking about Ubuntu ?

Yep: it’s Ubuntu V11.10 on a desktop that is ~6yrs old, with the original HDD.
The HD is partitioned with the original XP on the other one.
I first noticed the light always on a few months ago: I’m not very observant, but I’m sure it wasn’t always thus.
Smart Status: “Disc is healthy”

Does “Disk Utility” allow you to view the SMART data for that drive ?

Ah! Problem solved, I think.
Upon reflection, the ON light appeared to be continuous after moving the PC to a less well lit environment.
Audible disc access just brightens the light a bit, so I guess it’s supposed to show dimly the rest of the time.
Yeah, I’m a twit. Sorry to waste your time!

You know what, I’ve had this happen recently as well

Can you both install the iotop package:

sudo apt-get install iotop

then sent the output from

sudo iotop


sudo top

hopefully iotop should tell us which process is accessing the HDD, and top will tell us if the swap partition is being used.

Might also be a good idea to force a file system check (fsck) to run at next boot:

sudo touch /forcefsck

then reboot.


Sorry Keith … just spotted your last posting … up to you if you want to bother with this :slight_smile:

sudo iotop & sudo top seem to be running continuously but I attach to screen shots…
The system monitor indicated that there are no swap files in use.

@ Keith

I think you’re right about the power light just bleeding into the disk access light, as iotop doesn’t show anything accessing the HDD, and top doesn’t show the swap partition as being used :slight_smile:

Thank you, Mark.
iop & top appear to very fancy system monitors of some kind. Are they specifically for peripheral monitoring? And would they be useful for the casual user?
Any background info would be interesting, if you have the time.

top displays the processes that are currently the top users of system resources (RAM/Swap/CPU)

iotop does the same thing for I/O operations (Input/Output … aka, disk read/writes)

They just help you see what’s using what, so you can track down any errant processes … whether they’d be any use to a “casual user”, I suppose that depends on whether they like to see what’s going on under the hood, but they’re most often used for troubleshooting.

Thank you for taking the trouble to explain.
You’re a gent, as usual.

Sorry I didn’t get back to you Mark, I was in work.
I’m not really bothered about looking into it as it’s not that big a problem, just thought I’d mention it in case it was becoming an issue for many people due to an update.

No problem … let me know if you change your mind :slight_smile: