# Spinning disks down with ZFS



## bbzz (May 23, 2011)

Hello,

Is it possible to spin down disks/put them in idle/standby mode, which are using ZFS? I suspect there might be issues depending on how ZFS access these disks but I wasn't sure from the info I found. As a note, I tried both camcontrol(8) and ataidle. What happens is that disks do spin down but immediately spin up again after issuing these commands. After that however, they never spin down again. 

Finally is it even practical to spin down disks like this from time to time? The power consumption might add up with large number of disks, which might matter for something like home NAS solution/desktop.

Any suggestions welcome.


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## bbzz (May 24, 2011)

DD, why was my post edited (honest question)?

Anyone have suggestions on this topic?


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## DutchDaemon (May 24, 2011)

Added a camcontrol(8), and highlighted ataidle as a command using . Most edits on this forum are like that, and more people should write their posts like that.() manual page" href="https://www.freebsd.org/cgi/man.cgi?query= link to camcontrol(8), and highlighted ataidle as a command using . Most edits on this forum are like that, and more people should write their posts like that.&sektion=&manpath=freebsd-release-ports"> link to camcontrol(8), and highlighted ataidle as a command using . Most edits on this forum are like that, and more people should write their posts like that.()


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## AndyUKG (May 24, 2011)

Hi,

Don't have a good answer to your question, but as no one else has commented...: ZFS was designed for the data centre rather than home systems so it wasn't designed with the possibility to spin down disks in mind. The main problem is that ZFS will write data and meta data across all disks in a pool, so any activity will likely require to spin up all disks. However I have seen some posts where people claim to have had some success using the method you have, ie that they can spin down the disks and they remain spun down until there is some IO requested from ZFS. If its not working for you I'm not sure what to suggest.

Cheers Andy.


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## toddnni (May 24, 2011)

Hi.

I have two ZFS pools. Another one consists of two mirrored disks which I have set to spin down. The disks spin down perfectly when there is no activity on the pool, and any write activity will spin up the both disks. In addition, usually reads from the pool won't spin up the disks because of the cache (noatime set on filesystems).

I tried once to spin down disk which had a UFS root partition, but it immediately spun up as AndyUKG described.


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## bbzz (May 24, 2011)

Thanks guys, that's all I needed!




			
				DutchDaemon said:
			
		

> Added a camcontrol(8), and highlighted ataidle as a command using . Most edits on this forum are like that, and more people should write their posts like that.() manual page" href="https://www.freebsd.org/cgi/man.cgi?query= link to camcontrol(8), and highlighted ataidle as a command using . Most edits on this forum are like that, and more people should write their posts like that.&sektion=&manpath=freebsd-release-ports"> link to camcontrol(8), and highlighted ataidle as a command using . Most edits on this forum are like that, and more people should write their posts like that.()




DD, I swear I had those already! Which is why I asked. Sorry, somethings broken with you up there :D :D() manual page" href="https://www.freebsd.org/cgi/man.cgi?query=

DD, I swear I had those already! Which is why I asked. Sorry, somethings broken with you up there :D :D&sektion=&manpath=freebsd-release-ports">

DD, I swear I had those already! Which is why I asked. Sorry, somethings broken with you up there :D :D()


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## DutchDaemon (May 24, 2011)

Yes, you sort of had them in there. You were not using the  tag, which is much more convenient than looking up, copying, and pasting a URL -> [man=8]camcontrol[/man].()


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## bbzz (May 24, 2011)

Ah, gotcha.


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