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I am currently building a server which is going to contain 4 drives only used for backup and media storage. Those 4 drives alone are going to add additional $100 to the power bill when they run all the time even though it only is necessary for a few hours per day. As the system should be available on demand and also has other vms/services running on an "always on" system-drive, turning the whole system off is not an option for me.

Are there any hypervisors which are capable of turning these drives down as long as they are not being used?

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migrated from Jun 8 '13 at 2:09

This question came from our site for system and network administrators.

Home servers are off-topic on ServerFault. – Joel E Salas Jun 8 '13 at 2:04
Oh well, even though the virtualization topic suits serverfault more then superuser imo, let's see if this is going to produce any good answers. – Zulakis Jun 8 '13 at 2:12
Your question has nothing to do with virtualization! – Joel E Salas Jun 8 '13 at 2:14
And four hard drives costing $100 a month in power sounds extremely unrealistic, unless you live in the middle of nowhere and have to have electricity brought in via mule trains... – Michael Hampton Jun 8 '13 at 2:18
@Zulakis A brain surgeon is probably more qualified to give me a tetanus shot than a nurse, but I'm not going to demand that the brain surgeon administer the shot. – MDMarra Jun 8 '13 at 2:20

You didn't mention an OS, so let's assume you want to use a FOSS virtualization setup of KVM on Linux.

This link describes how to use hdparm to achieve what you want. Skip the beginning, it's junk.

Installing and configuring hdparm

I tested tools/modules like laptop-mode-tools, pm-utils en noflushd. But these did not work well. I had more success with hdparm. This command will not work on external USB hard disks, via SATA it works perfect. Open the /etc/hdparm.conf file and set the desired spindown time:

 # vi /etc/hdparm.conf
 /dev/sda {
#spindown_time = 60  # 5 min
#spindown_time = 240 # 20 min
#spindown_time = 250 # 30 min
#spindown_time = 280 # 1 hour
spindown_time = 340 # 2 hours
To check if the hard disk is standby, you can use the following command:
# hdparm -C /dev/sda

drive state is:  standby
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@OP: even if you do not use Linux you can boot a Linux liveCD and use hdparm to set the drive to spin down after a while. The command only needs to be issued once and the drive will keep that setting and will initiate spin down on its own, – Hennes Jun 8 '13 at 11:32

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