Host controller for SAS expander

[tucansam]

Hey gang.

 

I just picked up an HP HPE Smart SAS expander (https://h20195.www2.hpe.com/v2/getpdf.aspx/c04111623.pdf?ver=20) to use in a spare tower case I have.  I have three 5x drive cages in that tower and I want to support 15 disks in it, connected to my current unraid server.

 

Curious what sort of controller card I will need in the unraid server itself.  I've got an LSI in it now, controlling 16 internal disks.  Will a second LSI with a simple matching external port, and then cable, get the job done?  I'm sure I'm complicating this, it seems pretty straight forward, but I want to make sure I get the correct controller to support an SAS expander in essentially an external JBOD.

 

Thanks.

[JorgeB]

Any of the recommended LSI HBAs works, you can connect one cable for single link or two cables for dual link.

[tucansam]

A couple follow ups.

 

The expander that will exist in the JBOD is 3gbps.  This is for simple media storage, largely, so I hope that doesn't present a significant bottleneck.

 

The expander has one port on it (externally).  I hope that a single port-to-port connection between the server and the JBOD doesn't present a bottleneck.

 

Assuming I can get a 6gbps host adapter cheaply, I assume that if I connect a 6gbps controller to a 3gbps expander, it will work, it will just down-clock to 3gbps?

 

And one final.. Something like an LSI 9200-8E can handle 8 drives, right?  Vs a -16 which can handle 16?  Or does it not matter, because the expander is taking one external port and converting it two more internal ports?  Trying to figure out what sort of internal controller I need to get 15 drives in the JBOD.

 

Thanks.

Edited August 13, 2021 by tucansam

[tucansam]

Just picked up a 9200-16E and an 8088-8088 external mini-sas cable for cheap, hope it all goes together and works!

[JorgeB]

11 hours ago, tucansam said:

I hope that a single port-to-port connection between the server and the JBOD doesn't present a bottleneck.

If the expander suports SATA2 (earlier firmwares can only link @ 1.5gbps with SATA devices) you'll have around 1100MB/s usable for to all the devices with a single link.

[jrprinty]

@JorgeB Am I reading this correctly, does unRAID now support Multipath SAS connections?

On 8/13/2021 at 10:32 AM, JorgeB said:

Any of the recommended LSI HBAs works, you can connect one cable for single link or two cables for dual link.

 

[JonathanM]

2 minutes ago, jrprinty said:

@JorgeB Am I reading this correctly, does unRAID now support Multipath SAS connections?

 

Dual link != multipath

Two different concepts.

[JorgeB]

42 minutes ago, jrprinty said:

does unRAID now support Multipath SAS connections?

No, multpitath is for redundancy, not extra bandwaith, usually you connect two HBAs to the same expander for that.

[jrprinty]

Thank you @JonathanM and @JorgeB. I was hoping but figured I had read that incorrectly. 

 

Thank you for the clarification .