PCI device ordering

[dsr-mzpnVDyJpH4k7aNtvndDlA at public.gmane.org (Dan Ritter)]

On Mon, Nov 29, 2010 at 03:32:24PM -0500, Stephen Adler wrote:
> Hi blu,
> 
> I'm trying to upgrade a server from rhel5 to rhel6 to find that the 
> order by which the kernel "discovers" the attached devices changes. 
> Specifically, the mother board has 6 sata ports and I added 4 more using 
> a PCI-e card. Under the 2.6.18 kernel of rhel5, the on board 6 channel 
> sata controller is listed first and the PCI-e 4 port sata controller 
> comes second. When I boot up under 2.6.32 kernel of rhel6, the PCI-e 
> controller is seen first and then the on board 6 port controller is 
> "seen" second. What this does is jumble up the driver order so that 
> /dev/sda under the 2.6.8 kernel is now /dev/sdd under the 2.6.32 kernel. 
> Is there anyway to force the kernel to scan the onboard sata controller 
> first and then the PCI-e controller second?

Don't do that.

Mount by label or by UUID instead.

That way, it doesn't matter what order they're detected in, and
you can even swap around cables. (Boot drive detection
permitting, of course.)

-dsr-



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