Yesterday, I was testing out a few things and ran into a strange issue I can't explain.
I have a X8DTU-F system with a AOC-USAS2-L8E, which is basically a LSI SAS2008 based SAS controller in IT mode. This is a testing system and everything works as usual in this configuration. I use a USB flash drive to boot various OSes on this test system; in yesterday's case, it was CentOS 7 on USB drive.
Yesterday, I added another LSI SAS2008 based controller (H310 flashed to IT mode) in a PCI-E slot. The system POSTs just fine, but when it went to boot the USB drive with CentOS 7 on it, it just shows a blank screen with a cursor blinking; doesn't even show grub2 or anything else. At first I thought maybe my USB drive went bad, as i do use it a lot from machine to machine. But after much troubleshooting, the USB drive is fine, and so were a few others I tried, but none of them would boot this machine with the 2nd SAS2008 controller in it.
Once I removed the 2nd SAS2008 controller, everything goes back to normal and any of the USB drives will boot just fine. So, out of curiosity, I decide to try a swap, so I removed the AOC-USAS2-L8E card and just install the one H310/SAS2008 card alone. In this configuration, all of the USB drives boot just fine. The problem happens when I have both the AOC-USAS2-L8E + H310/LSI SAS2008 installed together.
What would cause this?
I have a X8DTU-F system with a AOC-USAS2-L8E, which is basically a LSI SAS2008 based SAS controller in IT mode. This is a testing system and everything works as usual in this configuration. I use a USB flash drive to boot various OSes on this test system; in yesterday's case, it was CentOS 7 on USB drive.
Yesterday, I added another LSI SAS2008 based controller (H310 flashed to IT mode) in a PCI-E slot. The system POSTs just fine, but when it went to boot the USB drive with CentOS 7 on it, it just shows a blank screen with a cursor blinking; doesn't even show grub2 or anything else. At first I thought maybe my USB drive went bad, as i do use it a lot from machine to machine. But after much troubleshooting, the USB drive is fine, and so were a few others I tried, but none of them would boot this machine with the 2nd SAS2008 controller in it.
Once I removed the 2nd SAS2008 controller, everything goes back to normal and any of the USB drives will boot just fine. So, out of curiosity, I decide to try a swap, so I removed the AOC-USAS2-L8E card and just install the one H310/SAS2008 card alone. In this configuration, all of the USB drives boot just fine. The problem happens when I have both the AOC-USAS2-L8E + H310/LSI SAS2008 installed together.
What would cause this?