frequent disk access

[lorebett]

Hi

I've been using kubuntu from some months now, and I noticed, using gkrellm, that even if I'm not doing anything, there are lots of disk accesses (per minutes), even when running on batteries (laptop mode); what is it that makes this happen? it didn't happen on Debian for instance.

any clue please?

[dibl]

Re: frequent disk access

All *nix operating systems "pulse" the filesystem periodically, like maybe every 15 or 20 or 30 seconds, regardless of whether there is any user activity going on. Out of curiosity I'm going to time it on mine tonight -- I'm away from it at the moment and can't state the exact rate of hdd access, but I'll edit this to post the figure.

Also, if you have the strigi daemon or anything like that running, it's going to be doing its indexing thing whether you are working on the system or not.

The only surprising part of your post is the statement that you didn't see this happening on a Debian system. I can assure it was happening -- perhaps you simply didn't notice it.

[lorebett]

Re: frequent disk access

the strigi demon is not running actually;

as for the Debian, I was referring when running on laptop mode; if it pulses the filesystem periodically the disk will never go to sleep... with Debian it was sleeping during inactivity periods... now there is basically no inactivity periods...

as for the unix systems periodically pulsing... I had never heard of that... what is pulsing the hard filesystem periodically?

By the way, the partition is mounted with noatime.

[dibl]

Re: frequent disk access

Ooops -- I did not mean to imply that "sleep" or "hibernate" or "standy" or whatever should not work on a laptop. It should -- depending on how yours works and the KPowersave settings that you use.

I simply meant that, when it's supposed to be running, every *nix system I've observed since 1992 will periodically flash the hdd access light -- they never stop doing that as long as they are running.

But a recent-model laptop should definitely comply with the KPowersave settings. I don't use a laptop, so I'm not expert on the setup -- probably searching this forum and/or Ubuntu Forum on your particular laptop model will yield information about setting it to hibernate according to your wishes.

[lorebett]

Re: frequent disk access

when running on batteries latopmode sets hdparm so that it stops the hard disk if there are no disk access for some minutes...

but if the system always access the hard disk this will never happen...

with debian the hard disk actually stopped... with kubuntu it does not...

so I guess there must be some process accessing it...

[Rog131]

Re: frequent disk access

I noticed, using gkrellm, that even if I'm not doing anything, there are lots of disk accesses (per minutes),

Only with gkrellm ?


There has been bugs like this:
Topic: Default HD power management settings will kill drive ?
http://kubuntuforums.net/forums/inde...opic=3087988.0
- > lot of load/unload cycles.

[lorebett]

Re: frequent disk access

I noticed, using gkrellm, that even if I'm not doing anything, there are lots of disk accesses (per minutes),

Only with gkrellm ?

well I'm using this tool to monitor hard disks, net usage, etc.
however, I also see the hard disk light flashing when gkrellm shows a disk access

There has been bugs like this:
Topic: Default HD power management settings will kill drive ?
http://kubuntuforums.net/forums/inde...opic=3087988.0
- > lot of load/unload cycles.

Yes I was actually aware of that and I applied the "ugly fix" that does not perform load/unload when running on AC.

My original question was actually related to that topic: when running on battery, being the hard disk continuously accessed, it brings to lots of load/unload...

[Rog131]

Re: frequent disk access

Are you using noatime option in the fstab ? I think that it should decrease read/write cycles.

From Linux: Replacing atime With relatime (about atime)

It's also perhaps the most stupid Unix design idea of all times. Unix is really nice and well done, but think about this a bit: 'For every file that is read from the disk, lets do a ... write to the disk! And, for every file that is already cached and which we read from the cache ... do a write to the disk!'"

Links:

Atime or noatime?
http://ubuntuforums.org/showthread.php?t=307672

HOWTO: Tweak your ext3 filesystem for a performance boost
http://ubuntuforums.org/showthread.php?t=107856.0

The atime and noatime attribute
http://www.faqs.org/docs/securing/chap6sec73.html

Linux: Replacing atime With relatime
http://kerneltrap.org/node/14148

[lorebett]

Re: frequent disk access

Are you using noatime option in the fstab ? I think that it should decrease read/write cycles.

yes, I'm using the noatime option (see my second post).

In the beginning I thought it was due to the atime, and I started to use noatime, but the problem remains...

[Rog131]

Re: frequent disk access

yes, I'm using the noatime option (see my second post).

Damn, sorry , time to go to sleep zzz...

[dibl]

Re: frequent disk access

If I had Gutsy on a laptop and was trying to cut down the battery usage in general, and maybe the hard drive accessing too, here's a great thread on the subject -- go to page 4 and continue -- lots of information and things to do.

http://ubuntuforums.org/showthread.p...wernowd&page=5

[dibl]

Re: frequent disk access

Here's more about a bug that causes excessive laptop hdd accesses:

https://bugs.launchpad.net/ubuntu/+s...ort/+bug/59695

Here's the linked workaround:

https://bugs.launchpad.net/ubuntu/+s...95/comments/14

And on this thread:

http://ubuntuforums.org/showthread.php?t=683370

it says that this command will work (after you have installed hdparm)(and assuming your hard drive is /dev/sda, which it normally would be in a lappy):

sudo hdparm -B 255 /dev/sda

[lorebett]

Re: frequent disk access

Here's more about a bug that causes excessive laptop hdd accesses:

https://bugs.launchpad.net/ubuntu/+s...ort/+bug/59695

Here's the linked workaround:

https://bugs.launchpad.net/ubuntu/+s...95/comments/14

And on this thread:

http://ubuntuforums.org/showthread.php?t=683370

it says that this command will work (after you have installed hdparm)(and assuming your hard drive is /dev/sda, which it normally would be in a lappy):

sudo hdparm -B 255 /dev/sda

As I said in my previous message, I already know about this issue, and already applied the fix: this reduces the load/unload cycles, not the disk accesses...

when running on batteries I prefer to have load/unload to save battery life, but I would also like the disk be accessed less often...

[lorebett]

Re: frequent disk access

If I had Gutsy on a laptop and was trying to cut down the battery usage in general, and maybe the hard drive accessing too, here's a great thread on the subject -- go to page 4 and continue -- lots of information and things to do.

http://ubuntuforums.org/showthread.p...wernowd&page=5

This provides lots of material, thanks!

I came to know about lm-profiler, and also that hddtemp, which I'm using, wakes the disk every minute! Probably that's the main reason about my problems...

I'll keep on investigating