[mythtv-users] Sata software mdadm raid spin down help

[Jonathan Rogers]

On Wed, 2007-09-26 at 23:24 -0700, genestapp at charter.net wrote:
> I'm not sure I'm doing this right. I'm currently using the command /sbin/hdparm -S 244 /dev/sd*  in rc.local to set my hard drives in sata raid arrays that are rarely used to spin down. Also for mounting purposes I have the fstab entry set to noatime. Looking at my kill-a-watt meter and listening to the drives, they never seem to go into a spin down state. Any ideas on what I am doing wrong and why the drives are not going into a spindown state after 2 hours. The drives in question are not the myth recording array but just high def storage that is rarely accessed, so no point paying for 50 watts of power usage.

Wow, you must have a really wide display. I have two SATA drives in my
MythtTV machine, one with the OS and recordings and the other has only
recordings. When I experimented with the the hdparm -S settings, I
couldn't seem to get the recordings-only drive to spin down when it had
no activity, even setting -S to very small values, though I could force
it with -y. However, checking the status now with -C, I can see that it
is in standby mode, so maybe I just wasn't patient enough earlier.

While testing, make sure nothing is accessing the drive by unmounting
any filesystems on it. I am not using MD, so I don't know how that might
affect it. I assume that it wouldn't need to access the drive when no
filesystem on an MD device is mounted, but I really don't know.

BTW, if the drives in question don't contain MythTV recordings, what do
they contain? I'd suggest that if they're rarely accessed, you probably
don't need RAID anyway. If you want to protect against drive failure,
you can use a periodic mirroring via rsync or something rather than
RAID.
-- 
Jonathan Rogers <jonner at teegra.net>
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