Determining hard drive state

[Kirk Bauer]

On Wed, Nov 25, 2009 at 9:45 PM, Alan Dayley <alandd at consultpros.com> wrote:
> On Wed, Nov 25, 2009 at 4:22 PM, Kirk Bauer <kirk at kaybee.org> wrote:
>> For the record, I have both ntfs and ext4 partitions on the drive,
>> both mounted at all times under Ubuntu 9.10, and the drive remains in
>> a "standby" state except when I'm actually using the drives.
>
> Interesting.  If I may ask, I'd like more details for my own education.
>
> How do you know the drive is in standby?

I know when it is in standby by running "hdparm -C /dev/sda" (as I
learned on this list).

> How do you know when you are actually using the drive?

For me, the only thing I have on the drive is my Windows partition
(which I virtually never use) and my data stores for VMWare Server.
So even though the drives are mounted, and even though VMWare Server
is running, until I actually access the Windows filesystem or
create/start a virtual machine, the drive isn't being used.

> As you start using it, is there any latency or pause before the access
> starts?  If so, how long does it last?  (Not looking for hard numbers,
> just a felt guess.)

Definitely a 2-second delay when I first access the drive when it is in standby.

> After you use it, how long before they go back to standby?

30 seconds (because of the -S setting below)

> Did you do any special settings or configuration to achieve this behavior?

Default Ubuntu 9.10 settings, except I added this to /etc/hdparm.conf
(not sure what the default would have been though).

command_line {
       hdparm -B 1 -S 6 /dev/sda
}