What program access hard disk every 30 second?

Question

I have a very loud hard disk. The hard disk make a very short noice every 30 seconds, even for a new boot. Anyway to check which programming access the hard disk repeatly so I can figure out if it's possible to make the machine quiet?

Answer 1

somthing I read about disk flush/sync timings.  There is some sort of 'laptop' mode in some kernels that if set will cause the disk to sync after a period of time in order to let APM/ACPI put the drive to sleep.
There may be settings for your filesystem to do the same(!?).  I remember old Windoze NT4 had similar problem and was not remedied until Win2k for use on laptops .... yuck, ... I said the W word.
Here's something I just dug-up:
Laptop mode ===========
This small doc describes the 2.4 laptop mode patch.
Last updated 2003-05-25, Jens Axboe <[email protected]>
Introduction ------------
A few properties of the Linux vm makes it virtually impossible to attempt to spin down the hard drive in a laptop for a longer period of time (more than a handful of seconds). This means you are lucky if you can even reach the break even point with regards to power consumption, let alone expect any decrease.
One problem is the age time of dirty buffers. Linux uses 30 seconds per default, so if you dirty any data then flusing of that data will commence at most 30 seconds from then. Another is the journal commit interval of journalled file systems such as ext3, which is 5 seconds on a stock kernel. Both of these are tweakable either from proc/sysctl or as mount options though, and thus partly solvable from user space.
The kernel update daemon (kupdated) also runs at specific intervals, flushing old dirty data out. Default is every 5 seconds, this too can be tweaked from sysctl.
So what does the laptop mode patch do? It attempts to fully utilize the hard drive once it has been spun up, flushing the old dirty data out to disk. Instead of flushing just the expired data, it will clean everything. When a read causes the disk to spin up, we kick off this flushing after a few seconds. This means that once the disk spins down again, everything is up to date. That allows longer dirty data and journal expire times.
It follows that you have to set long expire times to get long spin downs. This means you could potentially loose 10 minutes worth of data, if you set a 10 minute expire count instead of just 30 seconds worth. The biggest risk here is undoubtedly running out of battery.
Settings --------
The main knob is /proc/sys/vm/laptop mode. Setting that to 1 switches the vm (and block layer) to laptop mode. Leaving it to 0 makes the kernel work like before. When in laptop mode, you also want to extend the intervals desribed above. See the laptop-mode.sh script for how to do that.
It can happen that the disk still keeps spinning up and you don't quite know why or what causes it. The laptop mode patch has a little helper for that as well, /proc/sys/vm/block-dump. When set to 1, it will dump info to the kernel message buffer about what process caused the io. Be very careful when playing with this setting, it is advisable to shut down syslog first!
Result ------
Using the laptop-mode.sh script with its default settings, I get the full 10 minutes worth of drive spin down. Provided your work load is cached, the disk will only spin up every 10 minutes (well actually, 9 minutes and 55 seconds due to the 5 second delay in flushing dirty data after the last read completes). I can't tell you exactly how much extra battery life you will gain in laptop mode, it will vary greatly on the laptop and workload in question. The only way to know for sure is to try it out. Getting 10% extra battery life is not unrealistic.
Notes -----
Patch only changes journal expire time for ext3. reiserfs uses a hardwire value, should be trivial to adapt though (basically just make it call get_buffer_flushtime() and uses that). I have not looked at other journalling file systems, I'll happily accept patches to rectify that!