How to 'backplane' disks out of a chassis through a SFF-8644

schreibman

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May 1, 2023
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Thanks for your help in advance. Looking to add disks to my my truenas server. I'd love to re-use some existing equipment, and was wondering how I could accomplish the following:

Existing server has10 SATA drives that I'd like to access through the TrueNas server's open 8644 port (the 'E' off an LSI SAS9300-4I4E Storage Controller).
The existing server is always on, has good power, [used for compute and local storage uses NVM'e].
Currently all disks are mounted, powered, and FWIW currently connected to the existing servers mobo (local sata & HBA).
My brain is stuck on what I'd need to add to my existing server to pass those 10 disks across an 8644 to the truenas 8644 port.
(?) I'm thinking (?) I need something like an HBA/Extender with 12i 4e (8644) capacity, but just uses PCI for power and exposes the SATA drives to the Unraid server through the 8644.
Thinking I'm getting stuck on what type of card(s)/Cables would I need to accomplish this.
Thanks
 

sretalla

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I don't know that you can do it with external SAS connectors (maybe a converter cable of some sort), but what you would need internally to connect your HBA to would be a SAS expander.
 

jgreco

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My brain is stuck on what I'd need to add to my existing server to pass those 10 disks across an 8644 to the truenas 8644 port.

You need an SAS expander. This is like an ethernet switch except for SAS. Check out the SAS Primer.


This will take a single SFF-8644 with its four SAS lanes and make it into a bunch of SAS lanes that share the four backhaul lanes.

I suspect you need something like an Intel RES3FV288 which conveniently already has SFF-8644 on it for the backhaul, but you can also make use of ones with all SFF-8643 and get a converter backplate if you like. If you do not have a mainboard in the "other" computer with the drives, you may need to provide power to the expander (see the jack at the bottom, I believe it's for power). It does NOT have to be placed in a PCIe slot and is NOT an HBA or RAID card; it only vamps power off the PCIe bus. You can tape it elsewhere in a chassis if need be.

 

schreibman

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Joined
May 1, 2023
Messages
2
You need an SAS expander. This is like an ethernet switch except for SAS. Check out the SAS Primer.


This will take a single SFF-8644 with its four SAS lanes and make it into a bunch of SAS lanes that share the four backhaul lanes.

I suspect you need something like an Intel RES3FV288 which conveniently already has SFF-8644 on it for the backhaul, but you can also make use of ones with all SFF-8643 and get a converter backplate if you like. If you do not have a mainboard in the "other" computer with the drives, you may need to provide power to the expander (see the jack at the bottom, I believe it's for power). It does NOT have to be placed in a PCIe slot and is NOT an HBA or RAID card; it only vamps power off the PCIe bus. You can tape it elsewhere in a chassis if need be.

perfect, looked at the Intel RES3FV288 and was
1683082268805.png
.
36 ! ports / molex super easy.
thanks
 
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