modifying existing configuration to go to Supermicro SC847J SAS2 Chassis

ricka777

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Oct 6, 2020
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8
Good day,

I have an existing configuration running with12 disks. I tried creating a side-car from an old case running 12 more disks using esata, but daily I would get random errors that could be cleared, but returned randomly on different drives-presumably because of the esata connections. I ditched that idea and removed the side car. Additionally, the machine I have the 12 drives in is overloaded and running a bit hot.

I came across a SC847J 45 disk rackmount chassis, which I'd like to use. A PDF for it can be found here:
It has 2 backplanes: BPN-SAS2-846EL1 (24 port) and BPN-SAS2-847EL1 (21 port )

My machine has a LSI SAS 9207-8i controller (and I have a second one I am not currently using). I currently use (2x) 4-to-1 SAS to SATA cables for 8 Ironwolf drives, and 4 of the on-board SATA for the remaining 4 drives. I'd like to hook up 24 drives.

Does anyone have any experience going from a regular case hosting your drives in an external chassis like this one? I'm not very knowledgeable about SAS, I don't understand if I can hook up my LSI card to the chassis backplane directly and communicate with all 24 drives, or if I need a different card, or if I need something Supermicro specific. Some confusion because all SAS cards I see generally are referred to as 4 or 8 port, leading me to believe they can only communicate with 4 drives per connector.

Any help greatly appreciated, I'd like to get my drives out of the oven I created for them.

- Rick
 

Chris Moore

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May 2, 2015
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Your SAS controller can handle hundreds of drive by way of SAS expander backplanes. You just need the right cabling and you can put all your drives in that rack chassis and connect the chassis to your SAS controller. No problem. I will look for some photos to add to this post to help clarify the connectivity for you.
I do this kind of thing for work. Very familiar.
 

Chris Moore

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Click the images to see them larger

I came across a SC847J 45 disk rackmount chassis, which I'd like to use.
Like this?


The eight "ports" on a SAS controller are more appropriately called "communication lanes" and can be directly attached to individual drives or to a SAS expander. The backplanes inside that rack chassis have integrated SAS expander chips that spread the communication between the connected drives in a similar way to what a network switch moves data packets between the ports. Each drive can communicate with the controller and the controller can talk to the drives.

On the back of that unit are these external SAS connectors:
1608088019104.png

You connect to those with a cable like this:
1608088099043.png
Many vendors have these cables in different lengths, just make sure the model of the connector.

This cable set will allow you to turn the internal SAS controller into an external one:
1608088786629.png

Alternatively, you can purchase a SAS controller that was made to be external to begin with:
1608089075205.png

Or this one:


At work I have multiple external disk shelves attached to a single server. It is pretty easy as long as you follow the rules.
There is more documentation to be found on the internet, including in this forum, if you do some searching.
Here is an example: https://www.servethehome.com/external-sassata-disk-chassis-wiring-part-1/
Please ask if you have questions.
Better to ask than do it wrong.
 
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