SOLVED Find info on your LSI SAS HBA

[cyberjock]

PCIe 1.0 should still do 250MB/sec per lane per direction, so an 8x card like the M1015 would be able to move almost 2GB/sec. The card itself though probably has enough latency to affect throughput. Believe it or not but the older cards, when not bottlenecked by PCIe and such, sometimes add enough micro-latency that it adds up to slower total throughput. Of course, in their day it wasn't a limitation because of the speed of hardware at that time, so nobody cared. :p

If you lived in IL I'd see about putting my spare M1015 in your box "just to compare speeds" and other silly things. ;)

 

[sfcredfox]

If you lived in IL I'd see about putting my spare M1015 in your box "just to compare speeds" and other silly things. ;)

Now that's a true computer friend. Loans you a part for troubleshooting.
I'm in IN. Too bad, that would have been worth a few beers...

PCIe 1.0 should still do 250MB/sec per lane per direction, so an 8x card like the M1015 would be able to move almost 2GB/sec. The card itself though probably has enough latency to affect throughput. Believe it or not but the older cards, when not bottlenecked by PCIe and such, sometimes add enough micro-latency that it adds up to slower total throughput. Of course, in their day it wasn't a limitation because of the speed of hardware at that time, so nobody cared. :p

I have read a few posts about latency you guys discussed. I guess there's no real way to test that. I can't figure out if the individual drive performance is more to do with the HBA or the MSA70, or both. It's connected via 8088 SAS cable (maybe a 3 meter), and then there's the backplane/sas expander inside the MSA70 for the 25 drives. It could be crappy/high latency/all of the above. I have no idea.

At the end of this, I've done all I think I can with current hardware (by putting current 3801E at P16/IT mode), and I've added the 9207-8e to my 'purchase list' for the future. I now understand the chips to drivers relation a little better, and know what firmware I want when I get the new card, and how to check it once installed.

Thanks everyone, your knowledge is appreciated.

 

[cyberjock]

I have read a few posts about latency you guys discussed. I guess there's no real way to test that. I can't figure out if the individual drive performance is more to do with the HBA or the MSA70, or both. It's connected via 8088 SAS cable (maybe a 3 meter), and then there's the backplane/sas expander inside the MSA70 for the 25 drives. It could be crappy/high latency/all of the above. I have no idea.

I saw this firsthand actually. I had an old Areca 1280-ML24 (circa 2007 or 2008) and a 6Gb/sec M1015. The same drives, same pool and same hardware saw performance differences of almost 1GB/sec versus about 340MB/sec. ;)

 

[sfcredfox]

I saw this firsthand actually. I had an old Areca 1280-ML24 (circa 2007 or 2008) and a 6Gb/sec M1015. The same drives, same pool and same hardware saw performance differences of almost 1GB/sec versus about 340MB/sec. ;)

What did you change in this scenario? Remove the Areca and direct connect the drives? I am assuming the M1015 was not the culprit since it's the poster boy for good adapters...

 

[Ericloewe]

What did you change in this scenario? Remove the Areca and direct connect the drives? I am assuming the M1015 was not the culprit since it's the poster boy for good adapters...

I think he means he replaced the Areca with the M1015.

 

[sfcredfox]

I think he means he replaced the Areca with the M1015.

wow...duh sfcredfox

Thanks Eric. Now, time to wake up...

 

[Ericloewe]

wow...duh sfcredfox

Thanks Eric. Now, time to wake up...

Doctor recommends coffee!*

*Only slightly more qualified than Dr. Nick

 

[sfcredfox]

Would anyone care to comment on this card:

Mouse over image to zoom
Have one to sell? Sell now
LSI LSI00300 (9207-8e) PCI-Express 3.0 x8 Low Profile SATA / SAS Host Controller


This is the card mentioned above, and I believe FreeNAS is quite happy with it based on Eric's recommendation. It would be flashed to the P16 IT mode firmware and then I assume it would be quite happy with the P16 driver (MPS)?

*edit* forum is screwing up the link to ebay. Weird.

Card will be used with MSA70, so it will never get to do 6Gb speeds as MSA70 is limited to 3Gb, but as Cyber mentioned, it should be a much more supported chip than the 3801 I hope.

 

[Ericloewe]

The interaction between different SAS versions hasn't always been perfect. The card itself is ideal.

 

[sfcredfox]

Thanks. I guess I'll guinea pig mixing 6Gb card with 3Gb hardware and report if it's a disaster.

 

[Ericloewe]

It shouldn't be a disaster, that's what backward compatibility specs and firmware/driver updates are for.

Some weird limitations from SAS1 stuff are more likely.

 

[sfcredfox]

The only thing I am aware of currently is the limitation on 2TB drives. The MSA60 has 12 slots, I guess I can trade drive capacity for quantity. More power :/ faster rebuilds :)