I have a bit of a strange problem and at this point I’m stumped.  This issue has a long history but I will try to keep it brief.  Here’s what I’m working with:

 

Mobo: ASUS P7H55/USB3 LGA 1156 Intel H55 USB 3.0 ATX Intel Motherboard

CPU: Intel Core i5-660 Clarkdale 3.33GHz LGA 1156 73W Dual-Core Desktop Processor BX80616I5660

2x SAS Controllers: SUPERMICRO AOC-SASLP-MV8 PCI Express x4 Low Profile SAS SAS RAID Controller

Unraid Boot Device: SanDisk Cruzer Micro

Unraid version: 4.5.6

 

I have 16 2TB SATA 3.0 hard drives that connect to a total of 4 SAS ports on the two SAS controllers.  I recently upgraded to the motherboard above to give me an extra PCIe slot to run a second SAS controller.

 

When I boot my system each of the SAS controllers interrupts the POST process (they each have their own BIOS that they use to detect and spin up devices). 

 

If I boot my system with no hard drives in the bays I can see the “SanDisk Cruzer” as a boot option in my system BIOS.  But if I connect a drive to one of my SAS controllers the boot options change to include a SCSI device, and the “SanDisk Cruzer” is no longer recognized as a bootable device.  It attempts to boot off the SCSI device and since none of my drives have boot sectors the boot process fails.

 

The strange thing is that the motherboard I was using previously:

ASUS P7H55D-M EVO LGA 1156 Intel H55 HDMI USB 3.0 Micro ATX Intel Motherboard

With one SAS controller booted just fine without issue, but these SAS controllers appear to be altering the boot options in my motherboard BIOS such that I cannot boot with drives connected.  I’ve been wrestling with this thing for weeks now and I can’t figure out how to get around this issue.  Any help would be greatly appreciated.

 

2x SAS Controllers: SUPERMICRO AOC-SASLP-MV8 PCI Express x4 Low Profile SAS SAS RAID Controller

 

Since you did not mention it, so have you disabled "INT 13h" option in both Supermicro cards?

2x SAS Controllers: SUPERMICRO AOC-SASLP-MV8 PCI Express x4 Low Profile SAS SAS RAID Controller

 

Since you did not mention it, so have you disabled "INT 13h" option in both Supermicro cards?

 

No I haven't.  After searching the forums for that it appears that this setting prevents SAS cards from stealing boot priority.  That sounds like my problem so I'll give it a try tonight and report back.  Thanks!

We have somewhat similar setups.  I didn't make any changes to the USB settings, but I did go into boot priority for hard disks and disabled everything other than the Sandisk (highlight the non-Sandisk entries, hit enter, and set to Disabled).  This might be worth a try if you have no luck with the other option.

but I did go into boot priority for hard disks and disabled everything other than the Sandisk (highlight the non-Sandisk entries, hit enter, and set to Disabled).  This might be worth a try if you have no luck with the other option.

 

This might not work in some MB, as least i know it did not in my MSI MB. Because sometimes BIOS will re-arrange list base on latest device probing result. By disabled "INT 13h" those disks probed by Supermicro cards will not show up in the list of boot device candidate then you will not have this issue any more.

I tested this last night by replacing one of my SAS controllers with a graphics card (i have a headless setup with no on-board GPU).  I was able to get this working with each controller independently but I'll have to wait until I can get a PCIEx1 graphics card to setup both cards.

 

I tried setting each card independently, then pulled the GPU and seated both cards but it wouldn't boot up.  I assume that the cards weren't able to maintain state after being pulled from the mobo.  I've got an elcheapo graphics card on the way (I figured it might be good to have around). 

 

Based on my test last night I think it's safe to say that this will solve my problem.

 

Thank you for the help!