Hard Drive Spin Down

[Sam Leon <debian@net153.net>]

I have added a large drive to my desktop for back up purposes.  I am 
using rsnapshot to backup just a couple of times a week.  Since the 
drive will be rarely accessed I added:

/dev/sdb {
spindown_time = 180
}

To hdparm.conf to spin down the disk after 15 minutes of inactivity to 
save power (yea goin' green!)

Everything is working right except when I go to restart or shut down the 
pc.  When I do that, right before init runs halt the hard drive spins up 
and then the pc shuts off.  Does the hard drive have to spin up in order 
to flush a buffer or something before shut down?  Any way to get around 
this?  The sudden spin up and then shut off doesn't seem like it would 
be good for the disk, makes alot of noise when it does it too.

Is this just "normal" or what?

Thanks,
Sam