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Date: Mon, 09 Feb 2015 09:54:07 +0100
From: Zdenek Kabelac <zkabelac@redhat.com>
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Subject: Re: [linux-lvm] LVM disk power management
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To: LVM general discussion and development <linux-lvm@redhat.com>

Dne 8.2.2015 v 19:59 Drew... napsal(a):
> Hi,
> I have 3 physical disks forming one volume group, with one logical volume.
> If i try to issue a standby command to the logical volume i get the following
> error..
>
> |sudo hdparm -y /dev/mapper/VG0-LVstorage
>
> /dev/mapper/VG0-LVstorage:
>
>   issuing standby command
>
>   HDIO_DRIVE_CMD(standby) failed: Inappropriate ioctl for device|
>
>
> But if i issue a standby command to the individual disks in the volume group..
>
> |sudo hdparm -y /dev/sda1 /dev/sdb1 /dev/sdc1
>
> /dev/sda1:
>
>   issuing standby command
>
> /dev/sdb1:
>
>   issuing standby command
>
> /dev/sdc1:
>
>   issuing standby command|
>
> This works fine!
> Is addressing individual disks the normal way to to spin down disks in a lvm
> volume group or will this cause file corruption.
> And if not, is there a safe way to achieve this or is it just not possible to
> spin down disks in a lvm.
> I would be grateful of any advice you could offer. I have spent some time
> searching around for some information on this & i can not find any documented
> on this anywhere.
> Thanks,


Yes - you need to 'hdparm' control  'real' devices/PVs.
There is no point to try to control logical volumes.
Imagine you could have 1000LVs on a single PV.


Regards

Zdenek