Using two HBAs on one SAS Expander

[metaleggman]

If I put two LSI 9207-414e HBA cards into my server, and hooked up their SF-8088 ports to a JBOD with a two SF-8087 input SAS expander (like this one) via a SF-8088 to SF-8087 PCI adapter, would this setup work properly? Or would I be better off getting an HBA with dual SF-8088 outputs (like a LSI 9201-16e) and an HBA with internal SF-8087 connectors (like a LSI 9201-8i)? I need some extra inputs internally, as well as connections for a future JBOD enclosure. I'm not really sure if there are benefits or drawbacks to either, and they'd be about the same price, either set of cards. Thanks in advance.

 

[Nick2253]

I wasn't able to find good documentation on that specific SAS expander, but in general, the SAS expanders work with either one or two "input" ports, and then give you X output ports.

For the example you're looking at, you should be able to do all 16 disks using one SF-8087 port. If you want to use two ports, then your HBAs have to support multi-path IO. In my experience, this either "just works™" or is a huge pain to futz with.

 

[mav@]

"dual SF-8088 outputs and an HBA with internal SF-8087 connectors" would give you 8x wide-porting on the JBOD. It should work if 8-wide ports are supported by the expander. I am not sure it makes much sense for so small expander and old HBA, unless you have some vefy fast drives in that JBOD, but if you have spare cables I see no reason not to.

The other configuration with two cables from different HBAs to the same expander supposed to work in perfect world SAS theory, but I would not recommend it. I am not sure that all firmwares will handle it properly, plus it require multipath support from sortware, that creates unreasoinable additional overheards.

 

[metaleggman]

The other configuration with two cables from different HBAs to the same expander supposed to work in perfect world SAS theory, but I would not recommend it. I am not sure that all firmwares will handle it properly, plus it require multipath support from sortware, that creates unreasoinable additional overheards.

Yeah, it seems like it's overcomplicated something; I should use a KISS mindset for this upgrade lol. And yeah, ArtofServer told me I'd be plenty fine populating both the expander and the internal connectors for the cards I was speaking to him about, so I should be able to get away with just the one card anyways.

Thanks for the responses!