Project Saturn (Daphnis/v2.5) - HC4 and MooseFS - Scale-out Storage Fabric

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Late night coder
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Project Saturn (Daphnis/v2.5) - HC4 and MooseFS - Scale-out Storage Fabric

Post by Late night coder »

Hello,


Back in Jul 2020 I published details on this forum for a scale-out / distributed storage fabric based on the Odroid HC2 and the Ikea TJUSIG with MooseFS: viewtopic.php?f=98&t=39486

The Odroid HC4 is highly suited to be the controller in a horizontally scaling distributed storage fabric, and I was keen to increase the storage density beyond what the HC2 had offered whilst retaining a passive (fanless, room temperature) cooling solution.
odroid-001.png
odroid-001.png (433.66 KiB) Viewed 158 times
Note the controller frame here, standing the HC4 vertically behind the TFT display and the two hard drives that it manages. The Odroid HC4 is screwed on to the controller frame stand-offs using the screws that it ships with. There is a through-hole included in the controller frame design to ensure that access to the reset-switch is not impeded. This design also ensures that the infrared receiver is facing the front of the storage cluster (not used in Project Saturn) with all network and power connectivity via the back.
odroid-002.png
odroid-002.png (368.32 KiB) Viewed 158 times
I wanted to de-couple the physical drive enclosure's scale-out architecture from the controller's enclosure/mount, and took the opportunity to implement a common enterprise drive bay model (hot-swap bay style). These design goals were also blended with a strong desire to 3D print as much of the solution as possible, to leverage smarter design decisions to remove the need to purchase additional fasteners or fittings (via printable clips and feet that snap-on to the TJUSIG rack).
odroid-003.png
odroid-003.png (345.22 KiB) Viewed 158 times
I'd ordered enough of the HC4s and HDDs to build the next evolution of Project Saturn in Apr 2021. The design process was straight-forward but I went through two and half 3D printers trying to reproduce the physical components (mostly as I was new to 3D printing, which included some unfortunate printer choices). With a good/working 3D printer it is a simple solution to print with none of the parts requiring support.

The below shows the plastics testing rig, with PLA, PETG and ABS components being used in different combinations to ensure the final solution, under load, doesn't end up in a puddle on the floor. On the left is the PLA print (the feet, clips, controller frame, tft-mini display mount, and drive enclosures) with the PETG version on the right; and the alternating caddy prints as ABS then PETG (left to right).
odroid-004.png
odroid-004.png (489.28 KiB) Viewed 158 times
Project Saturn (Daphnis/v2.5) is not yet complete but given my time allocation this is likely to be the last significant project update before Xmas. Given that the physical solution appears to be production ready, I am sharing the project now in case others find it useful. All of the CAD files, STL/3MF printable objects and plenty of additional photos can be found at Thingiverse, where the materials choices resulting from the thermal testing have been captured in the "thing" descriptions: https://www.thingiverse.com/midnightcode/designs

The manual will eventually be updated, and shared via the Project Site: http://midnightcode.org/projects/saturn/daphnis/

I am about half-way through printing a production cluster, which means there's a good chance you'll beat me to it. If you do print up your own implementation then please share it and let me know what you think of it.


Thanks,
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odroid (Sat May 07, 2022 10:50 am)

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Re: Project Saturn (Daphnis/v2.5) - HC4 and MooseFS - Scale-out Storage Fabric

Post by rooted »

How many units are you building?

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Re: Project Saturn (Daphnis/v2.5) - HC4 and MooseFS - Scale-out Storage Fabric

Post by mad_ady »

Nice of you to share your work!
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Late night coder (Wed May 18, 2022 7:00 am)

Late night coder
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Re: Project Saturn (Daphnis/v2.5) - HC4 and MooseFS - Scale-out Storage Fabric

Post by Late night coder »

rooted wrote:
Sat May 07, 2022 12:38 pm
How many units are you building?
I ordered 10 units of the HC4 with OLED back in April 2021 after it looked like the enclosure model was going to be mechanically feasible. So the goal is to produce one TJUSIG's worth (10 x HC4, 20 x HDD) with 5 of the HC4s per shelf. There isn't a need for that much capacity at the moment, but I want to close out the Saturn/Daphnis work and there's a couple of large scale data modelling projects that have been deferred due to a lack of storage that could be back on the cards.

The 3D printing has been the biggest issue. The CR20 was slow to print PLA and it wasn't designed for ABS so I bought the Ender7 to make a production run with ABS caddies and fast PLA prints, but it just hasn't worked out:
  • I fought with it to get automatic bed leveling - there wasn't an off-the-shelf auto-levelling kit, then Creality pulled the Ender7 firmware for their CR-Touch sensor after I ordered it, so it took months to get to a working BL-Touch solution;
  • The Carborundum build plate deteriorated and eventually lost all bed adhesion, and no replacement plates were available in those dimensions;
  • After experimenting with G10 as a build surface (more lost order time) I found that the flip side of the supplied Carborundum plate, as a glass surface, was providing the better adhesion of the available options (though still with intermittent failures).
And that's setting aside other issues such as the extruder rate being accurate but one non-Creality filament brand producing brittle prints and another non-Creality filament brand producing too much material (neither were an issue on the CR20), etc ad nausea. However, at 4am last Sunday during another adhesion failure it looks like the print-head wedged the larger enclosure piece and broke the BL-Touch sensor. I am done with Creality.

As there are none in the country, I now have an Anycubic Vyper on order from Amazon. It will be slower than the Ender7, faster than the CR20, but hopefully it produces high quality prints, reliably. So it's safe to say that I'm not taking any Christmas orders ;-)

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Re: Project Saturn (Daphnis/v2.5) - HC4 and MooseFS - Scale-out Storage Fabric

Post by rooted »


Late night coder wrote: [*]After experimenting with G10 as a build surface (more lost order time) I found that the flip side of the supplied Carborundum plate, as a glass surface, was providing the better adhesion of the available options (though still with intermittent failures).
Interesting, I know several people who use G10 and love it. I ordered a sheet but it was far too warped to use so I never got to try it myself.

I use plain borosilicate glass on my printer with glue stick or painters tape when printing PETG, I don't use anything when printing PLA or TPU. I've not needed to print ABS fortunately but what I've heard is creating a slurry mix for your build plate with ABS and acetone makes for a nice adhesive for ABS prints.

I hope the Vyper will be better for you.

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