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DIY DAS Array


Swizzy
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So I've been looking into building my own DAS array to attach to my microserver gen8 with windows sevrer 2012 using a guide I've found on this website and some others. 


 


I'm looking at 12-16 3.5" bays over SAS for now and when I have more money I will most likely double it up. My plan is also to future proof. I have roughly 7tb RAID10 in my microserver gen8 and some more on other devices that I'd like to centralise so I would like a solution where I can just add more drives.


 


I'm still torn between getting a short depth server chassis with 12-16 bays or get something more economical and with a smaller footprint like the SilverStone DS380. Which brings me to my next question: If I were to go with the smaller silverstone enclosure how can I put them into a daisy chain or is that something not worth pursuing?


 


I also still have a bit of trouble getting my head around SAS HBAS, SAS Expanders and what the drawbacks and benefits are when it comes to adding more storage and bandwidth.


 


Asking for general advice I guess, and specifically what SAS controllers and expanders to use. I only have one 16x PCIE slot to work with in my microserver. Bandwidth isn't a major concern, anything will be better than what I already have and I do not plan to use SSDs for either storage or caching.


 


The link I mentioned: https://forums.servethehome.com/index.php?threads/guide-how-to-build-a-8-bay-das-enclosure-sata-sas.3666/


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Well, as for daisy chaining them, if you don't mind extra "hackery"....  get a second one of those internal/external SAS adapters, and buy a SAS Expander card, as well.  

 

By "hacky", you'll need to find someplace to mount the card inside the case, but something like the "Intel RES2SV240" SAS expander would be perfect.  It's 6 ports, so you could use 2 in and two out, to minimize the bottlenecking, and still have 2 ports for the 8 drive bays. 

 

Also, there are SAS switches:

http://www.avagotech.com/products/server-storage/sas-6160-switch

(I'm not sure about this, but it looks like it would work).

 

 

As for what SAS controller you want to use:

HBA: http://amazon.com/dp/B0085FT292/?tag=extension-kb-20

RAID: http://amazon.com/dp/B00BRE10JI

It's PCI-e 3.0, 8X, and not too expensive. 

 

 

 

But basically, SAS is kind of like Networking for DAS. Expanders act as switches and can be chained. 

However, like networking, each cable has a maximum bandwidth it can use, so the less you chain, the better. Though, each SAS cable can handle 3GB/s transfer speed, in theory. So you shouldn't have to worry too much. 

Additionally, IIRC, SAS is full duplex where SATA is half duplex, so better performance out of it. 

 

 

 

Also, instead of the silverstone box, Norco has a nice 8bay box that uses SAS connectors (so you only need the cables, rather than breakout cables, which makes it much easier to wire up). Check out the Norco ITX-S8 box.

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Thank you very much, that cleared a lot of stuff up, especially the networking analogy.

 

The one thing that stood out with the expander you posted is is that it does not have a power connector other than pcie which will be a problem, as I intend to run the enclosure without motherboard+cpu.

 

I find no shortage of expanders and HBAs, what worries me a bit more is compatibility with each other. Is it generally advised to use the same manufacturer for both HBA and expanders? I know a lot of them have similar, if not identical board design and controllers but it's still worth asking.

 

Since that Norco case you posted already has a backplane is the expander, drives and cables the only thing missing? It's a very tempting case, it will certainly be a close call between that and a 12-16 bay rack that has a backplane included, I've seen some competitively priced ones.

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The one thing that stood out with the expander you posted is is that it does not have a power connector other than pcie which will be a problem, as I intend to run the enclosure without motherboard+cpu.

The Intel RES2SV240 has a standard PC "molex" power socket on the top. You can power it either via the PCIe card edge or via that socket. If you do want to use the card edge then you need something like http://www.pc-adapter.net/products/692.html

 

I find no shortage of expanders and HBAs, what worries me a bit more is compatibility with each other. Is it generally advised to use the same manufacturer for both HBA and expanders?

I'd recommend it. The SAS expanders are generally specified to work with their own brand of controller. YMMV if you use it on anything else.

 

The generally available cheap SAS expanders are the old Intel cards previously mentioned which are 6Gbps for SAS + SATA or an old HP SAS expander but that only does 6Gbps for SAS and 3Gbps for SATA. The HP SAS expander has to be powered via the PCIe card edge. Have a look at http://hardforum.com/showthread.php?t=1484614for more information about these old cards. There are newer cards but they're significantly more expensive.

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I have more or less decided What I'm going with.


I've settled for a fractal design node 804. It has 10x3.5" built in already, PLENTY of cooling options and the side where the motherboard+cpu goes I can add 4-6 additional 4x3.5" hard drive cages with up to 26 drives as a rough estimate.


This is looking a lot cheaper than anticipated. As always, filling the thing with drives is what will chew my wallet thoroughly.


I have not yet exactly decided on which HBA I'm going for as I'm still planning and working out what my throughput might roughly be. I'd rather not shoot myself in the foot in the long run.


 


Fractal Design Node 804 £75


HBA £80ish off ebay


Expander (optional) ~£130


Power supply (undecided) ~£50


Additional 4x3.5 hard drive cages ~£20-50 each


Probably another £50 for cables and some other bits and bobs.


 


Thanks very much for the advice and insight, very much appreciated. When it comes to actually putting the thing together I'll document it all for this forum since this forum is what inspired me to try this.


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The Intel RES2SV240 has a standard PC "molex" power socket on the top. You can power it either via the PCIe card edge or via that socket. If you do want to use the card edge then you need something like http://www.pc-adapter.net/products/692.html

 

I'd recommend it. The SAS expanders are generally specified to work with their own brand of controller. YMMV if you use it on anything else.

 

Yup, this. It's one or the other though, not both. And depending on which version, it may or may not come with a PCI slot bracket. Bit it definitely has mounting holes, so you can be VERY creative about where it ends up (though, you may want to use mounting risers with it, just in case.

 

 

 

 

 

 

This is looking a lot cheaper than anticipated. As always, filling the thing with drives is what will chew my wallet thoroughly.

I have not yet exactly decided on which HBA I'm going for as I'm still planning and working out what my throughput might roughly be. I'd rather not shoot myself in the foot in the long run.

 

Thanks very much for the advice and insight, very much appreciated. When it comes to actually putting the thing together I'll document it all for this forum since this forum is what inspired me to try this.

 

 

 

Amen to that. Yeah, it's the drives that really take up the largest chunk of money. Even if you buy higher end parts. :)

 

And as for the HBA, I'd really recommend anything that uses an LSI chipset. You can't go wrong there. 

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Yes I keep hearing good things about LSI so I'm sticking with them. I hope it works well with that Intel expander, they're going for pretty cheap on eBay.

 

I'm even thinking about not getting an expander yet, as the HBÀ has 2 external ports ij can run 8 drives anyway and if I want more I'll get the expander and throw more drives in.

 

Moving drives from the HBA to the expander shouldn't mess with the data right? I have backups anyway but just curious.

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Yeah, the LSI are praised highly for a reason. :)

And it should work well with the Intel expander (which use an LSI chipset, IIRC). 

 

And no, moving the drives shouldn't mess anything up at all. In fact, I've done so, with no issues. Though my disks were not in a RAID array.

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