Experience with SAS3 attached to Supermicro SAS2 backplanes?

Pheckphul

Better than being feckless.
Feb 28, 2013
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SF Bay Area
Hello. I'm considering picking up a Supermicro CSE-847E16-R1K28LPB chassis with BPN-SAS2-846EL1 and BPN-SAS2-826EL1 backplanes. I've read that quality SAS2 interconnecting hardware will function at SAS3 when connected to SAS3 storage/HBAs. I am wondering what people's experience has been running SAS3 storage off of these backplanes.


Thank you for your time, and your input will be appreciated.
 

BlueFox

Well-Known Member
Oct 26, 2015
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You're definitely not going to get SAS3 speeds. That's a limitation of the ASIC in the expander. I have no issues with SAS3 drives with my SAS2-846EL1 backplane and have been running that for years.
 
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Pheckphul

Better than being feckless.
Feb 28, 2013
32
10
8
SF Bay Area
You're definitely not going to get SAS3 speeds. That's a limitation of the ASIC in the expander. I have no issues with SAS3 drives with my SAS2-846EL1 backplane and have been running that for years.
I was chatting with a person on Discord who said if you force the SAS3 to 12Gb instead of setting to 'auto' SAS3 speeds would be achieved assuming good SAS2 interconnects. Not true?
 

NablaSquaredG

Well-Known Member
Aug 17, 2020
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It depends.

This might work on a direct attach backplane, where the drives are directly connected to the controller.

The BPN-SAS2-846EL1 backplanes have an expander. That means your connection goes
HBA -> Expander Chip -> Drive

And the SAS2 Expander Chip is definitely not SAS3 capable. Sorry for that.
 
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