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I bugged the Odroid forum for info on the exact plug type. I went with these. 2,5 euro for 20 (I only need 12) and I'll just source the cables locally. I'm thinking of getting something like speaker cable since at the DIY store at least I could only find black wire. A spool of thread that's 10 meters long costs a little under 5 euro so this should work out to a total under 10 euro, if need be by simply using the one cable I need to get for the power solution anyways.

I've ordered that batch of plugs on the 22nd so it should arrive any day now.

I hope for you they fit. Like the quote of the offical website says to use 0.8mm insted of 0.7mm

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They told me here to use this size so that's what I chose.

But if it fails to perform I'm only inconvenienced to the tune of 3 euro. No biggie.

Edited by Cooper
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Received some goodies today. I got the ring connectors and the buck converter.
I also went to Ikea last weekend where I got some felt pads to prevent the bottom of the enclosure from scratching whatever surface I place it on.


Edited by Cooper
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I was running out of space in this forum for the pictures I had made so far. As a solution I've just set up a Photobucket account for this little project, uploaded my images to it and incorporated those in this thread.

If you just want to see the images (no promises on order) you can look here.

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Indeed. It's a consequence of the space constraints I guess along with the fact that few USB network adapters (as that's what it really is, just soldered to the board) support PXE boot and those that do have far more complex drivers because PXE boot is not a typical component of a USB class. This is the next best thing and should be quite workable though.

Come to think of it, by exchanging the MicroSD card I can change the identity of the board. If I wanted to do this using a PXE booting device I'd have to reflash the boot rom or reconfigure the server to cough up a different share based on MAC address. This could very well be the far easier solution to this particular problem.

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Interesting stuff but probably not usable for me since this is an ARM board and the bootloader is u-boot.

Here's the boot order plan:

At power on the u-boot bootloader kicks in, loads the full kernel from the SD card (in PXE scenarios you see TFTP used here because the flash is too small for the full kernel - not a problem here) and hands control over to it. Either via kernel parameters or simply via a file on the SD card the Odroid will be given its unique MAC address (default is random which bugs me on the DHCP front) and acquire its IP address from the DHCP server, which will have a fixed list of MAC -> IP address mappings unique to the cluster. At this point the Odroid can connect to the appropriate NFS share and mount its root filesystem. This, too, will be specified via kernel parameters.

The above scenario implies that the SD card will have to contain the u-boot bootloader, its configuration file which will specify the kernel boot parameters and the full kernel itself. Maybe a few more tid bits depending on how far I can get with this. If setting the MAC address from a kernel boot option is impossibly I might have to end up using an initramfs but I would very much prefer not to go that route.

We'll see.

I'd like to just mount an NFS share named /odroid-root or whatever which would be a different NFS server folder based on your IP address but it's probably easier to simply include the share path in the kernel parameters. I figured it would be simpler to maintain, but come to think of it there really isn't a bit benefit to it....

Edited by Cooper
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What benefits does it have? I'm looking at the talk but it's quite long so I don't think I can watch all of it today.

To repeat, I need it to run on ARM, I need it to cooperate with u-boot (there is NO WAY around that) and I don't have a MAC set within the adapter itself.

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it handles chainbooting. so your uboot will just boot the sd card. this would contain the gPXE that boots your os. it can boot iSCSI targets, pull over http ( wich you can send parameters like a MAC or ip or ... ) you can even setup a authentication. so the user can only select operating systems he has access to. The http is not restricted to local subnet. so you could load a image of a server on the other side of the world.

If you cant watch it all i suggest start near minute 50 then the fun things start.

OK last i found is that its not fully ported to arm. so your right its not usefull for udroid

Edited by GuardMoony
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I went and took another hard look at the fans problem. The problem being that they're rather expensive and essentially overkill.

The current crop of 92mm system fans is designed to cool gaming rigs and what have you whereas I simply want a mild draft to prevent heat build-up. One thing I didn't properly account for is that these fans are, indeed, 92 mm and not the 90 which I had originally drawn in a mock-up (not uploaded yet), but not to worry - it fits. The 3 fans side-by-side account for 276mm while the switch is 285mm so there's at least a little wiggle room.

So when I last mentioned the fans my idea was to use Arctic Cooling F9s. Not too loud, decent CFM, priced at just over 6 euro each. Having looked into it with a bit more detail I've now decided to get Sharkoon S922510L-3 fans which are low-speed fans. Just 1000 rpm where the F9 was 1800. Because of this they're (supposed to be) much, much quieter, which helps when you intend to put 3 next to eachother and have the thing sit on your desk pretty much constantly.

The other thing is that even though I will have a bit of airflow in the chassis, why specifically go with the fanless version of the ITX board considering it's 8 euro more expensive and otherwise identical to the fanned one? I could first take off the fan and see how she fares. Chances are it won't be required. And if it IS required it probably would've been for the fanless version aswell. I know, I know. Yadda yadda less efficient chip used to gets hotter blah blah. Whatever. It's the same chip underneath, except for a rating Intel gave it. It's going to be luck of the draw anyways, might aswell use it to save a little.

And finally, I noticed that the fan, the ITX and the PSU can be had from the same vendor here in .nl which puts the total price of that package high enough to be eligible free shipping.

Here's an updated view of the bill of materials. Green means I already own it or it's on order and has already been paid.


Edited by Cooper
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I've always been afraid that I wouldn't be able to get the right sort of knob to use to pull a tray out.

Up until now I've been looking at the standard knobs you'd see on cupboards and the like, but they tend to be a bit... well, clunky for my taste. They tend to be large and mostly smooth because you grab hold under the knob for the pulling. My needs could've been served with a grooved plug with a pattern to it that allows me to grip it.

So, thinking outside the box again I ran across the concept of a 'Lifting eye knob':


I'm rather liking this. Okay, the ring itself is smooth (and the image is a render - you can buy them a little coarser than this, especially when you want them cheap) but I think I'll be able to grab hold of this and retain a sufficiently powerful grip to pull a tray out with this.The one I've seen in the webshop of a local DIY sells them for about 1.50 a piece so, again, more expensive than the original idea, but I like this a lot better. I'll go there in the coming days and feel if they are as good as I think they are. The one in the webshop didn't come with threaded lump, instead allowing a bolt to screw into it, which could be beneficial as I could take a longer screw that fills up the eye a bit and possibly grab hold of it aswell for additional grip.

Yup. Happy.

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So I went to the DIY shop to look at these lifting eye bolts...

I found the M8 one I saw on the website. Man, that thing is ENORMOUS. So that wasn't going to be the one which meant I went looking for a smaller version of it.

So I gave up on finding a suitable part at this DIY store and ended up purchasing some 13 gauge wire for transporting the power within the power delivery system. It needs to be able to carry up to 60 watts (5V, 12A max) over a distance of about 50cm / 2 feet. I figured I'd better get some potent stuff here. Oddly enough I found get getting 5 meters of outdoor insulated wire with contains 3 insulated 13 gauge wires was cheaper than getting 2 spools of that same 13 gauge insulated wire. And as luck would have it, I had a coupon due to an earlier purchase and, unbeknownst to me, it turned out to be on special so I got 5 meters of the stuff for just over 8 euro where a single 5 meter spool of 13 gauge wire would've cost 6 euro. Win!


They ended up giving me a new coupon for 20% off of anything I buy next saturday. Meh. We'll see about that.

So I went on to the next DIY shop looking for a lifting eye bolt. Once there I found some of a rather more modest size, but they all had about half a centimeter of space under the ring itself at which point there would be a rim if you will - a brief widening of the threaded part. I don't want this ring to be sticking out an additional half a centimeter. The ring itself was already more than 1cm in diameter. So I kept searching and found a small, double-ringed turnbuckle. It was spot-on. At M6 the threaded part was large-ish but workable, I could get a nice, smooth end cap and washers for it. Perfect. The turnbuckle cost 2 euro a piece, but you'd end up with 2 lifting eye bolts so I'd only need 3. Expensive, but doable. Took some pictures of the parts and their price tags and went back to the first DIY store since I now had some idea of what I could be looking for. They may have an even smaller version of this turnbuckle, or a cheaper one.

Turns out, they did one better. It took some digging, but they have lovely packs of 6 (YES!) lifting eye bolts, 6 (YES!!) caps to fit on the ends and a big pack of washers that will also fit over the threaded part.


The idea is that the washer goes between the ring and the tray so that when I push the tray back in or if I were to screw the ring too tight into the plastic that contains it, the V-shape you have at the base of the ring would push the 2 pieces of plastic there apart. Using the ring I spread the load evenly and straight across across the construction without pushing apart. If I'd found this during my first visit I would've bought it immediately. Total cost of these parts is 5.55 euro. But since I now have coupon, courtesy of my previous purchase, for a 20% discount if I were to purchase next saturday, I'm holding off until then.

One other thing I noticed. The other DIY shop has the perfect chunk of spruce for this project. For 8 euro I can get a smooth chunk of wood that's 1200x200x18mm. I thought I could only get 1 meter long chunks, but as luck would have it, the cheapest chunk is exactly the size I need for my project. I also just noticed that somehow the wood for this never made it onto my BOM... Strange. Still feeling very content at the moment. :smile:

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I'm wondering if I need to paint or stain or do something to the wood to improve longevity? It's very soft wood so anything could dent it, which is something I wouldn't be too bothered about, but I can imagine wanting to run a wet cloth or something over it every once and a while, without having to worry about the thing rotting on me.

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Another small gift from my great friends in the People's Republic of China. And I'm not even being a smart-ass here. Those Chinese vendors make a point of addressing you as a friend rather than a customer, because to them, you're not. You're a business associate and to them that's a very different beast altogether.


So anyways, the plugs. I've opened one up so you see what's inside. I was a bit surprised by the size of the thing. The non-bending part of the plastic cover is itself just over 20 mm in size. The bendy bit at the end is another 15 mm. If I leave that as-is it would imply that two boards on a tray are rather more spaced apart than expected. So what I'll probably end up doing is drill a hole somewhere in the middle of the non-bending part and run the cable through there, cut off the bending bit and hot-glue it shut. What I should've done is purchase an angled connector, but those were rather more expensive than this. For the time being though, quite happy with these. I'm considering putting in a cable rail for the power cables on the tray itself that would guide the cables along the sheet of plexi on the side. As always, it must be strong enough to not snap off at the first sign of trouble while still allowing me to guide a new cable through if need be. I might just put another slanted bit of plastic in on one side between and another after the two odroids much like there's on the front on both sides. The last thing I want is to run the power cable across the heatsink of the adjacent Odroid.

No thoughts on the need for treating the wood by anybody? I'm currently leaning towards getting a mahogany- or cherry-colored stain and then apply some furniture wax. That should treat the wood properly, give it a nice, rich color that slightly hides the fact that I'm using what is indeed the very cheapest block of wood I can find and provides a protective finish allowing me to clean the thing with a wet cloth if need be.

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Yet another present from my friends in china:


Remember the buck converter that turns my 12V line into a new 5V line? You can set it to pretty much any voltage and this is achieved by turning the little screw on the blue block on the far end of the thing as it's displayed in the image. Now supposedly it's already set to 5V, but would you trust 400 euro of hardware to some friendly words of a Chinaman you've never met before nor are likely to meet again, or would you spend the princely sum of 8.50 euro on a multimeter and just check for yourself. Hell, I might check other things aswell. Can't imagine anything right now, but the ability to do so is quite comforting.

I think that kind of wraps things up in terms of small change purchases. I still need to verify the plugs work, but I'm confident they will. Come next payday the worst of my financial troubles will have passed and when the taxman returns me my hard-earned dosh I can start looking at acquiring the remaining bits for this project. However I will be holding that part off until the girlie's pissed off.

So, expectation management: I'll have some pics to show probably this weekend where I mock-up the bottom section of the build. I've fetched the harddisks and I have a stand-in Mini-ITX standing by. This'll help me come to grips with the final size of things.

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  • 2 weeks later...

Interesting update - HardKernel now have an EU distributor!

Buy it from Germany at 70 euro a piece ex shipping.

I had calculated that I would have to pay 840 euros for 12 Odroids bought directly from HK in Korea and hope I don't get shafted by the tax man. By purchasing from a German reseller the taxes are now THEIR problem and I just play a grand total of 845 euro for 12 Odroids all inclusive. Very, very nice indeed. :smile:

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  • 2 months later...

The current status is that it's still somewhat on hold due to financial difficulties resulting from my break-up. I had to do quite some additional/unexpected repairs on my house, acquire a new washing machine and dryer plus certain parts of my tableware (plates, dishes, cutlery) had gotten chipped or outright gone missing (BITCH!) so those had to be replaced.

Since there's now a european distributor for these boards in germany, alleviating the shipping cost problem, I'm now planning to get a whopping *2* boards before years end so I can get to work on building the sleds and basically get the full enclosure built. I did test the power plugs with my U2 and it was a perfect fit. They didn't change the connector when they made the U3 so I'm pretty sure this will work out just fine.

What I want to do with this once I have it is test some of the software I write in a real clustered setup. This setup would involve load balancers, multiple webserver nodes, multiple application nodes, multiple database nodes, possibly a clustered setup of some kind of queue/bus thing.

The layers to go through when processing an incoming request would be

1. Reverse proxy webserver (apache, nginx, other) cluster with a loadbalancer.

2. Application server (my own making) with another loadbalancer.

3. Database cluster

The Reverse Proxies won't be put under that much pressure so that'll probably just be 2 nodes and I'll probably have the Mini-ITX Atom be the loadbalancer to it which leaves me 10 nodes. I think the database cluster is best served with 4 nodes where 1 is writable and the rest deals with clients read-only, being fed any updates from the writable node via replication. That leaves me 5 application server nodes with 1 load balancer.

My goal is to see how much performance I can squeeze out of it.

Another idea I have is to set this up as a continuous integration development pipeline. It waits for a git commit and kicks in a clustered compile of all the sources, a static code quality inspection, runs all tests setup for it and puts the result of it all on a webpage for me to inspect.

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  • 3 months later...

Small update since it's been a while and given my other topic where I confiscate a component originally intended for this project I feel I should explain myself.

The plan thus far was to use a regular x86 ITX computer as controlling node and storage server to the cluster. Because I'm using basically a regular PC here I need the full ATX power plug to power it which resulted in me needing a beefy ATX PSU if I was to power everything from that one device. But I got to thinking about the power needs of the various components and particularly the harddisks. Those 2.5" harddisks operate on 5v. All the Odroids operate on 5v. The main reason to want that PSU is to be able to run an x86 Mobo off of it. Wouldn't it be cheaper/more efficient to just use another 5v ARM board as a controlling node, get a high-power 5v-only power supply and run everything off of that?

So I went searching and ran across this eBay offering for a 5v 40A switching power supply for under $25. To me, that's nothing short of amazing. It's smaller, fanless (though I intend to provide some fans in the eventual build), has at least 3 rails to attach everything to which works very well with my setup... All I need to do is find a nice, compact controller board that speaks Gigabit to the switch in the build and preferably also gigabit to my main network, but 100Mbit would do for me aswell. One of those PcDuinos would fit the bill, though I'm hoping that I find a board that can either provide 1x SATA + 2x GbE or 1x SATA + 1x GbE + 1x USB3.0 so I can use a USB3 Gigabit ethernet adapter to get the 2 I truly want.

Sadly, there are still a few more 12v components in the build - the switch for one. Getting laptop harddisks or even an SSD would make it a 5v device, but I'd have to buy a new one and I've got plenty leftover 3.5" ones though I'm now thinking I should just use 1 instead of 2. A possible solution here is to take an upconverter that can deliver 12v2A from a 5v source and see if I can power all the remaining 12v components from it.

I'm planning on installing the PS and the harddisk sideways so the depth of the thing will once again be dictated by the depth of the sled once it has 2 odroids on it, probably in the 12-14cm range rather than the current 20cm.

Edit: About that controlling node, one of these looks perfect - SATA, GbE and USB3 for under $20...

Edited by Cooper
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  • 3 weeks later...

They just released an interesting alternative to the U3.

Different processor, still 4 cores, 1 gig ram and there's java for it. All that for half the cost of a U3. Performance-wise it's about half that of the U3. Power consumption is a bit lower, but we're comparing "next to nothing" against "even less than next to nothing", really...

Major drawback: The connectors are facing the thin side. Since my planned placement of the boards is like this = having the connectors on that side means the sled gets wider if I were to go for these puppies. Still, a promising development...

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