General Help Expanding on LSI 9211-8i

[porkload138]

Hello everyone,

I have 2 servers with matching storage drives running on LSA 9211-8is to utilize 8 ports on each at the moment. These servers are in 20-bay and 24-bay 4U chassis's. I'm ready to expand and utilize the rest of the bays but RAID Controllers/HBAs/Expanders has been a struggle for me to understand without any prior experience. I want to keep the SFF-8087 connectors for all components.

The product listing for the 9211-8i says it can support up to 256 devices with expanders.

One thing that I can't seem to find a decent explanation or infographic of is... How does the expander connect to the HBA? Does a single cable run from the HBA to the Expander? Is this a specific cable? Does it need to go into a specific port? A rundown on this and maybe referencing the 9211 and compatible expander(s) would be super-helpful.

Thanks in advance for any help!

 

[j_h_o]

Usually a single cable (SFF-8087) goes from the HBA/controller to the expander, and then the expander connects to "all" the drives.
The expander will have 1 or 2 ports that accept connections from the controller (depends on the exact model, etc.)

RES2SV240 might be a good option for you.

https://www.intel.com/content/dam/s...boards/server/sb/e93121003_res2sv240_hwug.pdf page 19 shows more information.

 

[porkload138]

This makes a lot of sense. Thanks for the concise explanation.

It looks like the RES2SV240 has 2 input ports. The manual says:

•Supports 4 inputs and 20 outputs configuration
•Supports 8 inputs and 16 outputs configuration

Am I correct in understanding that a single 8087 input cable (4 channel) can expand to 20 channels (5 cables)?

If using 2 input cables, would there be higher throughput with 4 less channels? This is probably irrelevant to actual performance due to SATA drives being used but I'm curious.

 

[familybot]

Am I correct in understanding that a single 8087 input cable (4 channel) can expand to 20 channels (5 cables)?

Yes.

If using 2 input cables, would there be higher throughput with 4 less channels?

Theoretically, yes. In practice, depends on expander and controller. (see: HP SAS Expander Owner's Thread)

That last link is referring to another popular SAS expander by HP. That one can be had for $15 on ebay now but, relevant in your case, only supports SATA at 3Gbps (SAS @ 6Gbps with firmware upgrade).

There are a couple 10 yr old STH articles that are still applicable and may be helpful for you:

https://www.servethehome.com/sas-expanders-diy-cheap-low-cost-jbod-enclosures-raid/

https://www.servethehome.com/sas-expanders-build-jbod-das-enclosure-save-iteration-2/

 

[porkload138]

Awesome. Thanks for your help!