Periodic scratching of the HDD

nyk · Posted: Sun Jan 08, 2006 11:26 pm Post subject: Periodic scratching of the HDD

My amd64 works very well with gentoo, but there is one thing: the HDD has very short periodic activity every 5 second for no reason I can imagine. It has 1GB RAM, so it shouldn't need to swap. I don't use much RAM, right now just firefox in gnome and still scratching. Even right after bootup, before the first login.
Any idea what could cause this, or if it's for some reason necessary? I post my kernel config, I'm using gentoo kernel.

robbyt · n00b Joined: 11 Aug 2004 Posts: 32

does this happen if you're not in X?

also, try this:
http://packages.gentoo.org/search/?sstring=lsof

nyk · Posted: Mon Jan 09, 2006 4:53 pm Post subject:

Yes, also when not in X, just after bootup. I don't have automatic X startup, always do "startx". But the scratching is there before this.

tlopez · n00b Joined: 11 Jan 2006 Posts: 5

I have the exact same problem. I tried killing all of the background processes, but still get recurring disk access even when sitting in a shell. I tried running lsof but didn't see anything that might be the problem. I've considered using fam and trying to track it down that way, but I'm hoping there is an easier approach!

mmbrothers · Apprentice Joined: 24 Dec 2005 Posts: 224 Location: Boston

It could be pdflush.

robbyt · n00b Joined: 11 Aug 2004 Posts: 32

lsof yeilds nothing?

linuxtuxhellsinki · l33t Joined: 15 Nov 2004 Posts: 700 Location: Hellsinki

It could be just that drive, I've understanded that some drives are moving their heads almost all the time just to make some checks on the surface of disks or something like that ?

But there's program called lm-profiler in the package of laptop-mode which you can use for tracking down the programs which are using the hard-drive, try that.
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tlopez · n00b Joined: 11 Jan 2006 Posts: 5

I read up on the above mentioned articles, and eventually tracked down my problem using:

nokilli · Apprentice Joined: 25 Feb 2004 Posts: 237

kjournald, as in, the kernel thread that flushes the journal for journaliing filesystems to disk, right?

So I'm guessing my picking ext3 for the Powerbook here was a mistake. I see that there's a five second interval between commits but really even if it was 30 seconds or even a minute it would still be annoying.

The plan then is to backup my root partition, reformat using ext2, and then seeing whether the noise improves. Sound reasonable?

nokilli · Apprentice Joined: 25 Feb 2004 Posts: 237

OK, the above strategy turns out to be pointless since the drive activity goes away when the laptop is unplugged, so clearly it is capable of ceasing this drive activity even when plugged in.

The question is, how do we do this?

Zarhan · Veteran Joined: 27 Feb 2004 Posts: 1016

emerge laptop-mode-tools and configure the timeouts as you like in /etc/laptop-mode/laptop-mode.conf.

nokilli · Apprentice Joined: 25 Feb 2004 Posts: 237

Thanks for the tip. I note however that I'm using a PowerBook, and that laptop-mode-tools is ~ppc.

Also of note: /usr/src/linux/Documentation/laptop-mode.txt

Zarhan · Veteran Joined: 27 Feb 2004 Posts: 1016

nokilli · Apprentice Joined: 25 Feb 2004 Posts: 237

For right now however, I've come upon what seems like an adequate fix, I just set the power policy for when under AC power to "powersave" (I do this in a Mac-specific package called powerprefs). It seems to be working well so far (~60 minutes), but if I have to go deeper, I'll give laptop-mode-tools a try.

Thanks again for the info.