6 GPU rig with Ubuntu trouble (Ether)

[voxelot]

Hello and thank you for any help received.

I am trying to set up a 6 GPU mining rig for the first time
.
Specs:
OS: Ubuntu 14.0.4
Mobo: asrock H81 pro btc
ram: 8Gb
CPU: Intel
Integrated graphics: Intel
6x AMD r9 270's
PCI risers

Everything lights up and works fine but I can't get the graphics cards to behave properly.

If I plug in the VGA into any of the integrated on-board graphics while I have any of the AMD cards plugged in the OS goes to a black screen right before the login screen (I am still able to open terminal). I am able to operate normally if I plug the VGA into one of the graphics cards and tell the bios to use PCI. However when I go to mine only one of the 6 cards is used. The OS seems to recognize all of the other cards.

I installed all of the drivers correctly here is the output of the opencl showing the 6 cards
http://pastebin.com/VMdwNyRH

Here is my xorg.conf file
http://pastebin.com/ybqAryBA

I also have another xorg.conf file that was created with todays date appended to the file name, and for some reason this is the file you get when you nano /etc/X11/xorg.conf (even though the file name in the explorer is xorg.conf.08032015)
http://pastebin.com/tc49UCuV

I am trying to mine Ether and followed their setup and can mine with one card at a time using $ethminer -G --opencl-device 0 through 5. Although it only feels like one card is heating up. If i try to open two devices at the same time ethminer tells me I do not have enough enough memory on the card. The cards are 2Gb and ethminer uses 1.4Gb for the DAG. The error message says I only have 700Mb on the second card I try opening up which looks as though it's trying to load on the same card that's already mining.

Here's the error message.

[OPENCL]:OpenCL device Pitcairn has insufficient GPU memory.838860800 bytes of memory found < 1423739904 bytes of memory required

Thanks again for any help.

[Marvell1]

2 GB is close to the limit but it should work I use Ubuntu myself for my small rig with 3 more r9 390s coming on Friday

check the forums here for help


https://forum.ethereum.org/categories/mining





here are the instructions I used for my install


http://spacience.blogspot.com/2015/05/ethereum-gpu-mining-ubuntu-1404-lts.html


but this guide is much better you will have a better driver install for your cards if you follow this



https://forum.ethereum.org/discussion/2695/frontier-mining-setup-notes-ubuntu-15-04-geth-v1-0-amd-ethminer

[voxelot]

Marvell1

Thank you so much for providing the other tutorials. I was able to reinstall my OS and get all 6 cards running today.

I will say if anybody is reading this and having troubles mining ether. The DAG is ~1.4Gb and the cards with 2Gb are hard to get running.

I had to allocate more memory usage to each card before i could mine.

Code:

export GPU_MAX_ALLOC_PERCENT=95