Booting a SuperMicro Superserver

Barney Cordoba barney_cordoba at
Wed Aug 13 00:39:31 UTC 2014

So there is. But I still don't see how this can happen. The default is P0 first and P1 second and it certainly wasn't changed, but it still seems to boot from the second drive when both are present. It's almost like there's some logic that says "drive P1 has the same kernel booted the last time, so lets use that instead of the new one in P0".   It's happened more than once in remote locations that is a PIA to pop the 2nd drive. I'll have to try a few things. Easy enough to build a new kernel and see which it boots

On Tuesday, August 12, 2014 2:24 PM, John Nielsen <lists at> wrote:

On Aug 12, 2014, at 12:09 PM, Barney Cordoba <barney_cordoba at> wrote:

> On Tuesday, August 12, 2014 1:16 PM, John Nielsen <lists at> wrote:
>> On Aug 12, 2014, at 10:32 AM, Barney Cordoba <barney_cordoba at> wrote:
>>> A continuing issue (with 9.1 previously and now 10) is that FreeBSD occasionally (or always) seems to boot from the 2nd installed drive rather than the first. I'd be happy to debug this, but I have no idea if it's bootcode or a BIOS issue. Supermicro pleads innocent, but their bios guys are hard to work with and fairly arrogant if you don't specifically isolate something.
>>> The scenario occurs when ada0 is upgraded and has an incompatible kernel with other code on drive ada1.  (note that ada1 is a backup of the pre-upgrade ada0, so it's fstab points to ada0 for mount points). The system will boot and then modules will fail to load. It loads the kernel from ada1 and then mounts partitions from ada0; old kernel and newer modules.
>>> The problem is resolved by popping the 2nd drive. So there is nothing wrong with ada0 to cause it to bounce to ada1.
>>> My question: What would cause the system to boot from ada1 instead of ada0? Bios or Bootcode?
>> BIOS, most likely. If the disk controller in question is onboard you should be able to specify which disk(s) and what order they will be booted from. If not, you'll need to just say <disk controller> in the BIOS boot order then go to the controllers BIOS to say which disk(s) to boot from and in what order. I have recent experience with a SuperMicro box and an LSI controller; the latter allows you to specify a (b)oot drive and an (a)lternate. Yes, b comes before a. :)
> The bios only gives you one choice for "HDD". You can't select one of the 4 drives to boot from. You can specify USB or CD or HDD, but Not HDD2 or HDD3.

There may be a separate option controlling "hard drive boot order", and/or there may be a completely separate BIOS program for your drive controller with its own hotkey.


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