Supermicro 846 Barebones (+X9SRL-F) or combo with X9DRi-F?

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Mar 2, 2016
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Should I get the barebones case and get a X9SRL-F as @Chris Moore suggests? Or should I grab the combo with the X9DRi-F?

Here's my plan for the server:
  • FreeNAS virtualized with 6x 4TB NAS drives z2.
  • VMs for lab work.
Questions:
  • I'm not sure if I can run the X9DRI-F with just one CPU? I know there are some limitations on using all PCI-E slots. I'd like this option for power saving.
  • Is the backplane in the 846 - BPN-SAS2-846EL1 fast enough?

The reason I ask is because the combo with the dual socket is considerably cheaper.

Samples:
https://www.ebay.com/itm/Supermicro...989670&hash=item59017ef2d2:g:O-MAAOSwwppdwZte

https://www.ebay.com/itm/SuperMicro...592515&hash=item2f34716f8c:g:wUUAAOSw~p5dO3c3
 

jgreco

Resident Grinch
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May 29, 2011
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Yes, the X9D's work fine with a single CPU as long as you put it in the correct socket. One's running about ten feet away from me that way.

24 bays on an SFF8087 at 24Gbps works out to 1Gbps or about 125MBytes/sec. There is an argument that this is oversubscribed because a modern HDD may be able to manage 200MBytes/sec, but that is ONLY if it is doing straightline sequential reads, which if we're being honest about it, ZFS is highly unlikely to do.

It would be oversubscribed for sure if you had two dozen SSD's in there though.
 
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Mar 2, 2016
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24 bays on an SFF8087 at 24Gbps works out to 1Gbps or about 125MBytes/sec. There is an argument that this is oversubscribed because a modern HDD may be able to manage 200MBytes/sec, but that is ONLY if it is doing straightline sequential reads, which if we're being honest about it, ZFS is highly unlikely to do.

Thanks! I may need to learn more about backplanes... Does this one need 24 cables or only a few? Is the bandwidth limit per the backplane or per drive put into the chassis? I.e. is there a 24Gbps limit and that can be used over 4 devices? Or 1Gbps per drive?

Where do I go to learn what I'm implying above to make the right choice?
 
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Mar 2, 2016
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We have a nice SAS Primer you should read. Come back afterwards with any remaining questions...

I had that in a bookmark as a to-read during this build, thanks! Really helpful!

How do I know if a backplane is TQ/A/BE16 etc?

I'm assuming the "IT Mode RAID controller" is the onboard HBA correct? Why would using an non-onboard LSI HBA be better?
- https://www.ebay.com/itm/SuperMicro...592515&hash=item2f34716f8c:g:wUUAAOSw~p5dO3c3

I have an LSI controller in an off-site server.

* Any suggestions on a replacement CPU that's a little better than the 2620 that they come with?
 
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Inxsible

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