Hald and hard disk activity

[Matthew Kuiken]

John wrote:
> With a fresh install of Kubuntu 6.06 all appears to be fine except the hard 
> disk light briefly flickers every couple of seconds, even when I have left it 
> with nothing to do for a long while.
>
> Running "top" did not show anything major running, but the hard disk activity 
> is very brief, just often.
>
> Looking at "ps -aux" I started to kill processes. Eventually, I find that the 
> excessive hard drive activity can be switched off by killing the six 
> processes:-
>
> hald-addon-acpi
> hald-addon-keyboard
> hald-addon-storage
> hald-addon-storage
> hald-addon-storage
> hald-addon-storage
>
> I am assuming that the hardware abstraction layer daemon is concerned with 
> testing to see if any new devices are added such as USB items.
>
> What problems will I find if I kill these processes?
> Is there anyway around these?
> Does the hard disk activity matter (Will it cause the HD to wear out faster?) 
> or should I leave it alone and put up with the constant flickering of the 
> led?
>
>   

John,

I do not know what those processes do, but I'd guess that they are not 
really good to disable...

About the accesses, though, they will depend on the file system that you 
are using, and the options that it was mounted with.

For example, an ext3 file system will write to the journal every 30 
seconds, no matter what the system is doing.  All file systems will 
update inodes if atime is enabled in the mount options (this is most 
likely what you are seeing).

The only place this really makes a difference is in a laptop environment 
where it would be really nice for the drive to spin down for power 
savings when it is not in use.  To reduce the number of writes, I would 
recommend using reiserfs partitions mounted with the noatime flag on a 
laptop.  This will allow the drive to spin down when it is not in use.  
AFAIK, only a few programs such as Mutt use the atime flags for anything.

-Matt

PS, I'm headed out on vacation for 2 weeks, so I won't receive any 
replies to this email.  I'm sorry if this leaves more unanswered questions.