This last weekend, I added a Supermicro AOC-SASLP-MV8 controller card, allowing me to get my server up to 14 drives. I've actually got an additional 2 port SATA3 card that would bring me to 16 drives, but that didn't want to play nice once, and wouldn't allow the system to boot if I inserted the MV8 (I'll make another post about this).

 

What I'm wondering is... what sort of performance I should expect from this card, because so far, I've found it to be painfully slow.

 

I've got only 4 drives connected to it so far, all off one socket via a forward breakout cable.

 

Of these 4 drives, 1 is the cache drive, 2 are new and waiting for pre-clear, and 1 is an array drive.

 

My understanding was that because this is a PCIe 4x card, that was enough CPU bandwidth to get full speed out of 8 drives at a maximum of SATA 2 speed, more than enough for standard spinning disks. I'm not seeing this though...

 

I started a pre-clear on both the new drives, and the whole server ground to a halt. I was able to log in and load 'top' where I could see that the CPU was hovering at about 90%wa, which I believe means waiting for IO. The result of this is that the pre-clear performance slowed down to about 2.6 MB/s, and took about 10 minutes to update the progress screen to show me this, as opposed to the 10 seconds that it usually updates at.

 

If I only one 1 pre-clear, the %wa in 'top' is reduced, but it doesn't seem to make a difference to the performance at all.

 

I'm not sure if it will help, but I've added the syslog that covers the initial boot.

 

I guess I should add a few bits of info to this...

 

System is a Foxconn H67MP-S

Core i3 2100

4 GB RAM

unRAID 5.0beta8c

syslog.txt

err..

 

I didn't look at the syslog but..

That card can handle 8 sata2 spinners at full speed at once.

the CPU should not be doing much of anything when using the drives in normal conditions.

 

I'd guess you have some sort of hardware issue or conflict.

 

did you try the second PCIe slot?

did you check the bios for things that would effect the PCIe slot?

 

Perhaps you need to tweak some setting. also make sure it is not trying to use that slot for video.

 

 

Thanks for your tips Johnm, I moved the card into the other slot on the motherboard that was probably meant for the graphics card, and it seems to be working well now, with 2 simultaneous pre-clears going at the speed I would expect and 'top' reporting a %wa of between 20 and 30 - much better.

 

I actually selected my motherboard because it had 1 x PCIe 16x, 1 x PCIe 4x and 2 x PCIe 1x slots. I though this would mean that I would be able to fit 2 x AOC-SASLP-MV8 cards, 2 x 2 port SATA cards and with the 6 onboard SATA slots, get as many as 26 drives running from it! This may not be the case now however.

 

Before I mark this thread as solved, I'll wait for the pre-clears to finish and then move the card back into the earlier slot and confirm that this was the problem. I am concerned that I might have fixed it with a simple reboot.

Thanks for your tips Johnm, I moved the card into the other slot on the motherboard that was probably meant for the graphics card, and it seems to be working well now, with 2 simultaneous pre-clears going at the speed I would expect and 'top' reporting a %wa of between 20 and 30 - much better.

 

I actually selected my motherboard because it had 1 x PCIe 16x, 1 x PCIe 4x and 2 x PCIe 1x slots. I though this would mean that I would be able to fit 2 x AOC-SASLP-MV8 cards, 2 x 2 port SATA cards and with the 6 onboard SATA slots, get as many as 26 drives running from it! This may not be the case now however.

 

Before I mark this thread as solved, I'll wait for the pre-clears to finish and then move the card back into the earlier slot and confirm that this was the problem. I am concerned that I might have fixed it with a simple reboot.

 

I've heard of problems occurring when using some non-graphics cards in some graphics slots (even though everything is PCIe).

Me too, that's why I didn't put it in there at first... unfortunately it seems now that it's only the graphics slot that will work at full speed with this card on my board.