Do you use spin up groups?


jonp

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  • 1 month later...

A word on the various comments suggesting changing this to apply to shares instead of specified disk groups => DON'T !!

 

Spin-up groups are very useful if you have controllers that "freeze" activities on attached drives while another drive on that controller is being spun up (this is not uncommon).    But if you have, say 10 drives in a "Movies" share, you certainly don't want all 10 of those drives to spin up when you access the share.    On the other hand, if a media item you're streaming is on disk x, and you know that any access to disk y will cause disk x to "freeze" until y spins up, you'd most likely want to have x and y in a spin-up group, so when x spun up, so did y ... thus eliminating any hiccups in the streaming.

 

It's not a critical feature -- this is true of a LOT of the "bells and whistles" that are in the current release -- but it's VERY handy for those of us who use it.    It's very easy to test whether it's useful for your particular setup => spin down all drives;  start a stream from one drive;  and then, one-at-a-time, do an access to other drives and see if any of those accesses cause the streaming video to pause.    If so, you've found an interaction you can eliminate with a spin-up group.

Clearly it takes a while to identify all of the interactions -- but once they're all "mapped" you'll never again have a movie freeze because somebody else accessed the server.

 

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Very True garycase. I honestly have never put anything on a User Share. I've always moved files around based on Disk Shares to make sure all video files of a particular video stayed together to insure there are no freezes or buffering, but that is the way I keep my files organized. Do I think you should remove the SpinUp Group option? No because it does appear some users actually use it, but like mentioned before unRAID and drives have come a long long way in speed.

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Note that spin-up groups have absolutely nothing to do with user shares => whether you use them or not has no bearing on the problem the spin-up groups resolve.

 

I also keep all files associated with a given video on the same disk.

 

But if my wife is watching a video on the main TV, and we have a guest (son, grandson, friend, etc.) who decides to watch a video in another room, if the video they want to watch is on a different disk, then I don't want the action of spinning up that disk to cause a freeze on the video already being watched => but this will happen in many cases if they're on the same controller.    My drives are all assigned to spin-up groups that I carefully identified (as I outlined above) ... so this never happens.

 

Considering there are only two of us, it's clearly not a big deal => but it's not all that unusual for my wife to watch a movie while I'm "fiddling" with the server (adding content) and occasionally we'll have a couple grandkids who are watching things in other rooms as well.    So it's very handy to have the spin-up groups.

 

 

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4 minutes ago, NAStyBox said:

Aside from that I don't know how it works completely either.

In a nutshell, you tell it that whenever say disk 8 spins up to also spin up disk 10.

 

IMHO Its only useful for a share that spans multiple disks where any delay in accessing a file from one disk and then accessing a file from another disk is completely unacceptable due to the need to spin up the other disk.  IE: Music shares.

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1 hour ago, NAStyBox said:

I guess if you have an array full of 1tb drives it might be useful. I just haven't found a need for it so it's still disabled. Aside from that I don't know how it works completely either.

 

Actually it doesn't matter if you have an array of 10TB disks => if two disks are on a controller that will "stall" access while spinning up a connected drive, then putting them in the same spinup group will eliminate a "freeze" in a movie being streamed off of one of the disks when some action on the server results in the other drive spinning up.

 

1 hour ago, Squid said:

IMHO Its only useful for a share that spans multiple disks where any delay in accessing a file from one disk and then accessing a file from another disk is completely unacceptable due to the need to spin up the other disk.  IE: Music shares.

 

I think most of us have all files associated with any given video or music album on the same disk, but what a spinup group will do is eliminate a "freeze" in what's being streamed from a disk if another disk on the same controller is spinning up.   Doesn't matter if there's any content for the share on that 2nd disk -- if it's on a controller that will "stall" all access while a drive is spinning up, then putting the drives connected to that controller in the same spinup group will eliminate this issue.

 

If you keep all your drives spinning;  or if you don't have multiple users using the server whereby a drive might need to spin up while some other drive on the same controller is streaming a video to another user (or if your controller doesn't have this issue); then spin-up groups aren't needed for your situation.   But anyone who has a controller that exhibits that behavior can definitely benefit from them.

 

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1 hour ago, NAStyBox said:

In order to get to 10tb of music I think I'd have to cross into the genre of Kazakhstanian Folk Music.

 

It's not an issue of how much music you have -- it's a function of if you have two shares on different disks that happen to be on the same controller and that controller has the "stall while drives are spinning up" characteristic.

 

Suppose you have all your movies on one disk;  all you music on another.   Someone in the house is watching a movie; and you decide to play some music.    When you start the music, the disk with your music share needs to spin up -- and this could cause the movie to "freeze" while that disk was spinning up.     [The opposite could also be true -- if somebody was listening to music and then a movie was started the music would stop for a few seconds.]     This is what spin-up groups can prevent.

 

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41 minutes ago, NAStyBox said:

That could be a problem with WMC because every live feed buffers to disk. It doesn't like hiccups like that. Enabling it now. THANKS!

Some controllers don't have the issue, some do. It won't hurt to enable it, but you may be spinning drives that don't need to spin. I'm not aware of an easy way to figure out if you are effected other than to manually do tests, copy with speed monitoring from one drive and spin up the rest one at a time to see if the copy pauses. Repeat for each controller group, to see what spin up requests do or don't effect.

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I started my unRAID life after IDE (okay, the motherboard had the controller, but I always used SATA drives and ignored the IDE ports)... and never really had much use for spin up groups.

 

Now that hard drives are very large and also very power efficient (<= 5W each) I have no concerns about letting them spin for several extra hours, or even 24/7/365. Where I am 100W of constant consumption for 23 HDDs costs me $0.31 daily, which is far less than the cost of a daily coffee -- and I don't drink coffee, so I'm still well ahead!

 

I generally set my spin down time to about 6 hours which lets them stop as I sleep, and usually they won't be called upon again until the next afternoon.

 

There's always delays the first time or two I try to access the array, but it's not a big deal after that as the rest of the day is hiccup free due to the long spin down timer.

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1 hour ago, jonathanm said:

Some controllers don't have the issue, some do. It won't hurt to enable it, but you may be spinning drives that don't need to spin. I'm not aware of an easy way to figure out if you are effected other than to manually do tests, copy with speed monitoring from one drive and spin up the rest one at a time to see if the copy pauses. Repeat for each controller group, to see what spin up requests do or don't effect.

 

Agree (as I noted earlier, not all controllers have this issue).     It takes a good bit of experimentation to confirm this; but you only need to do that once.    I did it a long time ago for my media server (5-6 years ago); and it's now completely "glitch free" for all media streams.    As noted above, another way to resolve this is to simply leave all of the disks spinning.

 

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It's not useful just with certain controllers. It's also useful if you use a single PC to access multiple things on the server at the same time. A PC using SMB makes a single connection to the server. So, the whole network connection hangs while the PC waits for a drive to spin up, even if the hard drive controllers in unRAID can keep responding. If you're playing a video on one monitor and try to access any other file using the second monitor you could get a pause.

 

Of course, this means the spin-up group could include all disks if you truly had a need to fix this SMB issue.

 

The original intent was for the master/slave IDE channels. But, it was found that even with controllers that didn't pause a PC would have hang-up issues if it was multitasking. In my testing, I could access spun-down drives all I wanted from another PC, but if I did it from my media PC while it was playing a video file, the video file would pause unless I used a player that could be set to use a big buffer.

 

I have no idea if NFS also has the issue, but I suspect not.

 

 

On 5/16/2017 at 8:26 PM, NAStyBox said:

Ah hah! That's the part I was missing. So if ANY disk spins up it could disrupt things like a video feed on ANY OTHER disk.

So I run Windows Media Center serving up to 7 extenders at one time. That could be a problem with WMC because every live feed buffers to disk. It doesn't like hiccups like that. Enabling it now. THANKS!

 

If your PC is using SMB and WMC requests a file that is on a disk which takes time to respond then all network traffic pauses until the disk is spun up and the file is made available. This being an issue or not is something you'd have to test, unless you don't use SMB as the connection.

 

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NFS won't have the freeze issue IF you're seeing it due to SMB waiting for another drive to spin up.   But if you have a controller that causes the issue while another drive on the same controller is spinning up then the network protocol in use really won't matter.

 

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I don't use them. My unraid box only has SSD's anyway. Spinning up/down is purely a legacy function from my perspective.

 

On spinning harddisks, this is something that can be automated perfectly. Power management should be able to handle spinning disks up/down when it makes sense. There's absolutely no need for anyone to configure this manually, unless in case of a control freak. Better not clutter unraid with unneccesary functions, iyam.

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