Arch Linux

louimjac

Member

Registered: 2009-04-16

Posts: 13

Freeze due to super high hard drive access. pdflush?

Hi everyone!

I've been experiencing troubles with my laptop for a while now, I can't get my hand on what's wrong.
The symptomes are a complete freeze (except for the mouse), even Ctrl-Alt-Backspace won't do anything. The hard drive light in on continuously, which almost never happens otherwise.

However when I'm running iotop in a terminal (if I'm fast enough I can do that before the complete freezing, and therefore monitor the I/O activity), I see either nothing (meaning absolutely no command is accessing the hard drive, except for system-ng from time to time, with a zero write or read speed), or a 100% I/O from pdflush.

Running "top" doesn't show abnormal activity.

Do you know what could be wrong there?
I'll be real glad to have some help, I had to reboot my system once again to write this post, it doesn't seems like a good solution!

Thanks a lot!

louimjac

Member

Registered: 2009-04-16

Posts: 13

Re: Freeze due to super high hard drive access. pdflush?

I forgot to mention, after a while the hard drive may sometimes calm down and everything goes back to normal.

R00KIE

Forum Fellow

From: Between a computer and a chair

Registered: 2008-09-14

Posts: 4,734

Re: Freeze due to super high hard drive access. pdflush?

Maybe mlocate is doing its thing ..... I have removed it because usually I use find and not locate and because it would always get in the way in the worst times.

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R00KIE
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louimjac

Member

Registered: 2009-04-16

Posts: 13

Re: Freeze due to super high hard drive access. pdflush?

well I'm not sure... First of all I'm using locate all the time. I could switch to find I guess, but if I could chose, I'd stick with locate.

Second, I don't think it's any kind of database refresh, because it happens several times a day, and moreover when I run updatedb manually my computer doesn't freeze at all.

louimjac

Member

Registered: 2009-04-16

Posts: 13

Re: Freeze due to super high hard drive access. pdflush?

I'm doing (or trying to do...) a back-up of my system on an external HD, using rdiff-backup in command line. it takes an awfully long time, I'm wondering how normal this is...

Iotop gives me an average of 98% of IO from pdflush, is this normal?

R00KIE

Forum Fellow

From: Between a computer and a chair

Registered: 2008-09-14

Posts: 4,734

Re: Freeze due to super high hard drive access. pdflush?

It shouldn't be normal for pdflush to do that, at least as far as I know. In my system it does behave properly.
On the backup side of things it is normal for it to take a long time, specially if you have lots of data to copy (many GB). What I am used to see is a peak transfer rate of 30MB/s when reading or writing to an external usb HD, and that is peak transfer rate, usually it's more like between 20MB/s and 30MB/s, so all you need is to do the math with how much data you want to copy and how fast you can copy it.
Also copying big files is usually faster than copying many small files.

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R00KIE
Tm90aGluZyB0byBzZWUgaGVyZSwgbW92ZSBhbG9uZy4K

louimjac

Member

Registered: 2009-04-16

Posts: 13

Re: Freeze due to super high hard drive access. pdflush?

Ok, thanks for the hints.
I really think I have something really wrong going on, even though I can't get my hand on it. rdiff-backup crashed twice, so I can't make a proper back-up. I copied/past all my important data by hand onto an external harddrive, but even that wasn't going smoothly : some files, such as pictures for example, weren't readble anymore. (about 10 .jpg files over 50Go of pics, so not a lot but far enough to be really anoying)

In fact my entire system seems to be quite unstable, maybe the issue is much deeper : on Dolphin, Kwrite or Kile my wallpaper appears as background of active window when I scroll up or down for example. I reinstalled all packages, using

sudo pacman -S $(pacman -Qq | grep -v "$(pacman -Qmq)")

but it was of no effect.
Do you have any idea of how to  diagnose such deep overall trouble?

Thanks a lot for trying to help though, I really appreciate, especially given the fact that I've been posting on this forum for weeks now about all that and that nobody around seem to have any idea, or any ... let's say time, to get into it!
And I don't really wan't to give up this computer and buy a Mac, I would prefer to keep Arch so I'll keep fighting!

R00KIE

Forum Fellow

From: Between a computer and a chair

Registered: 2008-09-14

Posts: 4,734

Re: Freeze due to super high hard drive access. pdflush?

Well ... not many ideas here too but
1) Can you still see the pictures from the "source" (your internal HD)?
2) Have you tried to test that external hard disk with another pc to check if it is working properly? (put it to its pace, copy lots of data from/to the external HD)

If you can maybe get hold of an external box for the HD in your pc and try to copy the stuff you have the in another pc.

Maybe your problem is just a bad usb cable, I've seen other people complain about some strange problems here and it turned out to be just a bad usb cable.

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R00KIE
Tm90aGluZyB0byBzZWUgaGVyZSwgbW92ZSBhbG9uZy4K

louimjac

Member

Registered: 2009-04-16

Posts: 13

Re: Freeze due to super high hard drive access. pdflush?

The external HD is working fine, the problem seems to come from the internal one. I can't read the corrupted files from there, a fortiori can't I download them to the EHD.
And as I had many troubles appart from this external HD (which I connected to back-up because of those trouble) I'm sure that the problem is in the PC.