Hi im currently looking into a solution to consolidate my stack of 5 external drivers and also have redundancy while also not being a power hog.

 

Of course the first thing that came to mind was the drobo. if I were to go that route I would have to get the new drobo fs to suite my needs, which would put an almost £600 hole in my pocket. Which makes it a lot less appealing.

 

Plus ive always been a diy kind of person. Ok so heres my questions.

 

Firstly power consumption is something im worried about, im looking to build a low power system it only has to suite my needs which is mostly backing up and storing media ill copy over from the htpcs around the house.

 

Im aware that unraid spins down drives when they are being used. But what about the main system? I dont have need for it to constantly be on but at the same time I dont wish to have to boot it when it is needed. Is there a way to have the system in standby (not just the disks spundown) and then it wake up when its being accessed or something  along thoughs lines?

 

Or does anyone have any experience using atom based motherboards? Id have to do some research  on the power consumption, but maybe if it were low enough having it go into standby wouldnt be an use.

 

Does anyone actually know the annual running cost of an atom based unraid machine? With say 6 drives? (over time when they are replaced ill be using low power ones)

 

ok so secondly is using an atom bassed motherboard an option? What are the cpu requirements? There are a few boards aroudn with a dual atom 330 which can have 6 sata drives via a daughter board.

 

The case I was looking at using is the following

 

http://www.quietpc.com/gb-en-gbp/products/pc-cases/fd-array-black

 

has anyone has any experiences with it?

 

Ok onto a few software-ish questions.

 

Im aware that unraid uses the largest drive for its backup data. Would I be correct in thinking that if I had a 1tb drive for the backup drive and then for example had 5tb drives id have 5tb (well whatever they comes to once formated and so on) of useable space?

 

Also if when 2tb drive prices come down I were to replace one of the drives with a 2tb, what would happen? Would that drive become the backup drive and not actually give anymore useable space unless I were to add a second 2gb? I believe drobo works in this way.

 

Im aware that if one of the data drive fails, id just need to swap it out and have it rebuild the drive. But what if the backup drive were to fail? Would it just rebuild that drive from the data drive when I swaped it out? Ive used raid in the past and had drives fail on me and losing the whole array

 

I think thats about it for the questions

 

any recommendations for low power hardware (really would it to be down to the same sort of consumption level as a drobo, which a read cost about £40-50 a year to run)

 

thanks

 

-Ryan

Im aware that unraid spins down drives when they are being used. But what about the main system? I dont have need for it to constantly be on but at the same time I dont wish to have to boot it when it is needed. Is there a way to have the system in standby (not just the disks spundown) and then it wake up when its being accessed or something  along thoughs lines?

Yes, there are scripts you can add that will shut down the entire server to S3 sleep mode when it is idle as long as your motherboard supports WOL (Wake On Lan). 

Or does anyone have any experience using atom based motherboards? Id have to do some research  on the power consumption, but maybe if it were low enough having it go into standby wouldnt be an use.

There are many using atom basd boards and putting them to sleep too.

Does anyone actually know the annual running cost of an atom based unraid machine? With say 6 drives? (over time when they are replaced ill be using low power ones)

That would depend greatly on your usage and local power rates.

ok so secondly is using an atom bassed motherboard an option? What are the cpu requirements? There are a few boards aroudn with a dual atom 330 which can have 6 sata drives via a daughter board.

Just about any cpu from a pentium 1 up will work.  unRAID is not cpu intensive at all.  You can add-on and build it into a virtual machine host, but that is not for the beginner and certainly not part of the stock unRAID product.  If you run VmWare, or run a torrent server, then the extra CPU horsepower will help.  If you add on a slimserver service and want to encode video on the fly, you'll want the cpu horsepower, but to simply serve up movies, even at HD rates, just about any CPU from a Pentium 1 upward will do.

Im aware that unraid uses the largest drive for its backup data.

Not for backup data, but for "parity" data.  They are very different.  Forget the term "backup drive" when it comes to unRAID.  It is a parity drive.  It contains calculatins base don the data on the other disks.  For an explanation of how parity works, see this this:

http://lime-technology.com/wiki/index.php?title=FAQ#How_does_parity_work.3F

 

Would I be correct in thinking that if I had a 1tb drive for the backup drive and then for example had 5tb drives id have 5tb (well whatever they comes to once formated and so on) of useable space?

Yes.

Also if when 2tb drive prices come down I were to replace one of the drives with a 2tb, what would happen?

You cannot replace a data drive with one that is larger than the parity drive.  You can at any time replace the parity drive with a larger one, so, you could replace the parity drive with the 2Gig drive and then re-use the parity drive as a new data drive.  You would gain 1Gig of storage.

Would that drive become the backup drive and not actually give anymore useable space unless I were to add a second 2gb? I believe drobo works in this way.

You assign drives... not the software.  So, if you were to assign a new 2TB drive to a data slot while a 1TB drive was the parity drive the array will not start and will give an error message something like this:

Stopped. Disk in parity slot is not biggest.  If this is a new array, move the largest disk into the "parity" slot. If you are adding a new disk or replacing a disabled disk, try Parity-Swap.

 

The "Parity-Swap" it is referring to will allow you to use a drive larger than parity when replacing a data drive when it has failed.  You assign the existing parity drive as the data drive, and assign the new, larger drive as the parity drive.  When you then start the array the contents of the parity drive will first be copied from the old disk to the new and then, in combination with the other data drives, used to re-construct the failed drive.

Im aware that if one of the data drive fails, id just need to swap it out and have it rebuild the drive. But what if the backup drive were to fail? Would it just rebuild that drive from the data drive when I swapped it out? Ive used raid in the past and had drives fail on me and losing the whole array

If the parity drive fails, you just replace it.  All the data drives in the array will then be read to construct the parity data stores on the parity disk.    If a data disk fails, you just replace it and press the "Start" button to begin the reconstruction process.  (There is a button labeled "restore" on the interface, it is poorly labeled, it is actually better described as a "Delete Disk Configuration and Invalidate Parity" button.  It would be NOT be what you would want to do with a failed drive unless you did not intend to replace the drive, and did not care about its old data, and wanted to re-calculate parity without the old drive or its data.)  Basically, unless removing a disk from the array and you do not intend to replace it, never press the button labeled as"restore"  Always press "Start".

 

If two drives fail at the same time you lose the data on those two drives only.  If you have a full array of 19 data drives, the other 17 drives would still contain their data.  The administrative goal is to never let a failed drive stay in the array for any length of time before replacing it.  If a drive fails, it is not the time to wait for a holiday sale.

 

Many of your questions are answered in the wiki:  http://lime-technology.com/wiki/index.php?title=Unofficial_Documentation

and in the hardware forum http://lime-technology.com/forum/index.php?board=9.0  You are not the first to want a low-power server.  You are not the first to want it to go to sleep when not used.  You are not the first to want it to be quiet.

 

Joe L.

The UK Version of the Budget Box Recommended Build may help you get started.  Note that it is based on a MicroATX motherboard, not a mini-ITX motherboard.  This means that it will not work with the case you linked above.

 

I haven't gotten around to making a mini-ITX based recommended build yet, but hopefully I'll get to it soon.