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Supermicro MoBo/Chassis HBA/LSI Setup

Western Digital Drives - The Preferred Drives of FreeNAS and TrueNAS CORE

Guinea

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Aug 1, 2017
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84
So I am working on a custom built NAS designed for high intensity Plex Media Server utilization. Here is the parts list I ended up going with:

  • Chassis - Supermicro 846BE16-R1K28B
  • Motherboard - Supermicro MBD-X10SRH-CLN4F-O
  • Memory - Crucial 16GB ECC RDIMM DDR4-2400 x2 (32GB)
  • CPU - Intel Xeon E5-1640 v4
  • CPU Cooler - Noctua NH-U9DXi4
  • Boot Drive - Samsung 850 Evo 120GB
  • HDD - 8x WD Red 4TB's
I have everything in person and have begun hooking everything up. I am a little confused on how the SAS configuration works. On the backplane of the chassis, I see 6 ports for SAS connectors (8087 I think?). I am assuming that each one is tied to 4 HDD's. I am not sure how to determine which port connects to which HDD slot. Should I be spacing them out to be read faster across more bandwidth or just lumping them together? Eventually I will have all 24 bays in use, but I am planning to do a FreeNAS ZFS configuration with 8 drive vdevs and expand by adding 2 more vdevs to the vpool as space is needed.

On the motherboard I see these 2 black square ports for SAS Port 0-7. I was under the impression that with this motherboard in particular, it has built in LSI, so an HBA would not be necessary. So how do I connect the HDDs to the motherboard? What cables do I need? This is all new territory to me and I have been researching a lot. I just want to make sure I am getting the right parts for the components I have. It is hard to find someone doing what I am doing in this configuration. Hopefully that makes sense.

I did some research and I THINK my backplane is the SAS2-846EL, as described by https://www.supermicro.com/manuals/chassis/tower/SC846.pdf

There is a lot of new terminology to me on here. There are 6 8087 ports available (Primary J0-J2 and Secondary J0-J2). You can use them for failover or other configurations. It is not clear to me how to hook these things into the motherboard. The motherboard has 2 SAS3 ports (SFF-8643). I want all 24 bays to be accessible (even though only 8 have drives in them for now). I would like it all set up so I can just pop in 8 more drives and add a new vdev once I need more space. Is there somewhere I can read or a video or something I can watch to explain how this all works together? I want to make sure I grab the correct cables.
 

Pezo

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Joined
Jan 17, 2015
Messages
60
I'll try to list what I could gather from the manuals of the parts you mentioned.
  • The Mainboard provides 8 SAS3 connections via two Mini-SAS HD connectors (SFF-8613 or SFF-8643 according to Wikipedia).
  • The backplane has 4 primary SAS2 connections via an SFF-8087 port, connected to an expander, which connects to all disks.
  • From what I gather you can use the second and third backplane connectors only for cascading (though I don't know when you would use which one).
  • You can use the secondary ports for MPIO (Multipath IO), but I don't know if that's possible with your motherboard. I also read that this will probably not work.
So for a first setup you would use one SFF-8643 to SF-8087 cable to connect one of the mainboard ports to J0 (the rightmost port) on the backplane. This should give you access to all drives through 4 SAS2 connections (24 Gbit/s total).

edit: In case you do have the SAS3-846EL backplane, you need one SFF-8643 to SFF-8643 cable to connect to J50 (the left one of the right two connectors) on the backplane. This will use 4 SAS3 connections (48Gbit/s total) and again give you access to all drives.
 
Last edited:

Ericloewe

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Feb 15, 2014
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In practice, it boils down to this:
  • Is that an expander backplane? If so, connect it using a single cable to the SAS controller (Use whatever combination of SFF-8087 and SFF-8643 you need, depending on what's SAS2 and what's SAS3)
  • If it's not an expander backplane, you need to either connect all drives directly to a controller, four at a time (SFF-8087 and SFF-8643 carry four SAS channels), or get a separate expander, connect them all to the expander and then use one port on the expander as the upstream to the HBA.
There are 6 8087 ports available (Primary J0-J2 and Secondary J0-J2).
If you do have a dual expander backplane, you just wasted a lot of cash. Anyway, just connect one of the expanders (you could try connecting it with two cables for extra bandwidth, but this is generally useless and has been known to not work properly).
So how do I connect the HDDs to the motherboard?
SFF-8643 to SFF-8087.
 

Guinea

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Aug 1, 2017
Messages
84
Ok perfect! That is what I was hoping would be the answer. I will grab a single 8087 to 8643 cable. It doesn't make sense to use 2 cables connected to PRI_J0 and SEC_J0 to the motherboard to increase bandwidth? Everyone keeps saying it does not work.
 

Ericloewe

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It should work, but experiences have been decidedly mixed. With mechanical hard drives, you're not going to get any benefits.
 

Guinea

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Aug 1, 2017
Messages
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Ok awesome. So one single 8087 to 8643 cable and I will have access to all of my drives and all the bandwidth I need. That is exactly what I was hoping. Thanks!
 

Chris Moore

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May 2, 2015
Messages
10,062
Ok awesome. So one single 8087 to 8643 cable and I will have access to all of my drives and all the bandwidth I need. That is exactly what I was hoping. Thanks!
You didn't post back on this, but I am guessing it worked since you are now back to add more drives.
 
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