[mythtv-users] I can't get my HDD to spindown when idle

[kanetse at gmail.com]

I'm trying to get my MythTV backend server to spindown its HDDs after
a given period of time in order to save power and reduce unnecessary
heat generation.

My videos are stored on /dev/hdd, and it spins down fine.

However, /dev/hdc only contains the /home mount and it never seems to
spindown.  I have set:

/sbin/hdparm -S120

... on both drives.  If I use hdparm from the command-line to spindown
/dev/hdc, it works fine, so I know it's not a hardware-issue. 
Something must be keeping the HDD active, but I don't know what it is,
or how to find out.

I have already moved all cron jobs/scripts to another mount, not on this drive.

I am running Fedora Core 4.

1) Any ideas what is keeping my HDD spinning up?
2) Is there a linux commandline tool I can use to find out what
processes have open filehandles? Specifically on /dev/hdc if possible.

Thanks