SAS3 controller not compatible with SAS2 Backplane???

[Fritz]

Case is a SM386 (Could be a SC385, it's a Dell case so it doesn't say). MB is a Supermicro X10SRH-CF. Upgraded the Backplane from a TQ to a SAS2 and all manner of weirdness appeared. Slots disappearing, Certain combos of HD's causing slots to disappear, etc. For example, had 4 SATA 8TB drives in the first row and the lower drive did not show up. Removed it and replaced it with a 3TB SAS drive and it worked perfectly. plugged in another SATA drive in said slot and it refused to show. Shuffled drives around the various slots was like playing wacka mole. Disabled the onboard SAS3 3008 controller and installed a Dell H310 and all is back to normal. It appears to me that the SAS3 controller isn't compatible with the SAS2 backplane. Or could it be something else?

TIA

 

[Dreece]

Sounds like faulty cabling to me, 99% of the time it usually is the cabling. That other 1% is made up of 0.5% faulty hardware and 0.5% user error, though faulty cabling could be potentially classed user-error too, though that would be a whole different political discussion.

Sorry couldn't be more helpful. Backplanes are backplanes, they should just work unless they're doing some fancy expander magic that the controller isn't aware of, however the hardware you mention should all be compatible.

 

[Fritz]

Sounds like faulty cabling to me, 99% of the time it usually is the cabling. That other 1% is made up of 0.5% faulty hardware and 0.5% user error, though faulty cabling could be potentially classed user-error too, though that would be a whole different political discussion.

Sorry couldn't be more helpful. Backplanes are backplanes, they should just work unless they're doing some fancy expander magic that the controller isn't aware of, however the hardware you mention should all be compatible.

Thanks. I found the cable in my cable box. No idea where or when I got it. One end is SAS3 and the other is the standard plug that plugs into a SM backplane. Are these directional?

 

[Dreece]

Never heard of directional SAS cables before.

It was always a bit misleading to call the cables SAS3 vs SAS2 etc.
8087 plugs have the same internal wiring as 8643, so should support all the way up to 12G, but 8088 plugs (external) don't and max out at 6G.

If you don't have access to another cable right this minute, you could just try doing an electrical continuity test, a little fiddly with the probes but you can determine if the cable is bad that way.

Is the replacement backplane you have there a direct-attach one? or is it an expander one?

 

[Fritz]

Never heard of directional SAS cables before.

It was always a bit misleading to call the cables SAS3 vs SAS2 etc.
8087 plugs have the same internal wiring as 8643, so should support all the way up to 12G, but 8088 plugs (external) don't and max out at 6G.

If you don't have access to another cable right this minute, you could just try doing an electrical continuity test, a little fiddly with the probes but you can determine if the cable is bad that way.

Is the replacement backplane you have there a direct-attach one? or is it an expander one?

The backplane is a SAS2 836 EL1 expander backplane. An SAS3 backplane will have the same connector as a SAS3 HBA. In my case I'm going from SAS3 HBA to a SAS2 backplane. Different connector on each end. The previous backplane was a direct connect TQ. I know it would work with SAS3 using the proper cables but I would need 4 SAS3 ports to populate all 16 slots and the MB only has 2. I would need to add another 2. All the HD's are 6G's or SATA3's so using the builtin SAS3 HBA is just a convenience. Right now I'm using a LSI SAS2 HBA and all is well. I've disabled the onboard SAS3 HBA's and hopefully they're not consuming any juice.

 

[Dreece]

Yes the SAS3 supermicro backplanes (both expander types and direct-attach) have the 8643 ports and the SAS2 supermicro backplanes have the 8087 ports.

It could very well be that the onboard SAS3 chipset doesn't understand the expander, you could probably confirm this with Supermicro. Or maybe the firmware revision on the backplane and/or board is old. Though I recall reading an article some gent wrote on updating the firmware on his supermicro backplanes, can't recall what the reason was.

Either way, as long as you have the drives up and running you're live.

ps. just touch the onboard sas chip, if its hot, its using juice, if its cold, its not. Not very scientific, maybe a lukewarm temperature represents its powered but not doing anything, but hot represents its running at full pelt even though you're not using it.

 

[Fritz]

Yes the SAS3 supermicro backplanes (both expander types and direct-attach) have the 8643 ports and the SAS2 supermicro backplanes have the 8087 ports.

It could very well be that the onboard SAS3 chipset doesn't understand the expander, you could probably confirm this with Supermicro. Or maybe the firmware revision on the backplane and/or board is old. Though I recall reading an article some gent wrote on updating the firmware on his supermicro backplanes, can't recall what the reason was.

Either way, as long as you have the drives up and running you're live.

ps. just touch the onboard sas chip, if its hot, its using juice, if its cold, its not. Not very scientific, maybe a lukewarm temperature represents its powered but not doing anything, but hot represents its running at full pelt even though you're not using it.

Ah, thanks. I'll do some more research.