SCSI disk names change when adding / removing devices.

Jeff Vian jvian10 at
Mon Jul 12 07:15:21 UTC 2004

On Mon, 2004-07-12 at 01:00, Naoki wrote:
> Ok, I understand that cheers, but I'm not having a problem with the
> ordering of the devices it's the ordering of the controllers.
> I have two controllers.  The first, and LSI ( the internal ), and my
> newly added Adaptec.
> The LSI is detected first by the Bios and the Adaptec second ( which
> is what I want ). So why would the adaptec be assigned sda and my
> internal disks get sdb ?
> That's what's breaking things for me. Because my internal disks are no
> longer sda1/2/3 my kickstart build fails (or installs onto the
> external array which I really don't want).
> Anything I could do here, I think it's the hardware being funny and
> presenting itself to the kernel in the wrong order perhaps?
> -n.
Ah,  internal and an add on.  You don't have the choice of relocating
the controllers then.  However, as the driver modules are being loaded,
you can specify the order they are loaded so the first one loaded gets
the title scsi0 and the second gets scsi1.

With my ethernet adapters I was able to use something like
alias eth0 8139too
alias eth1 3c59x
to specify the card with the 8139 chip was eth0 and the 3com was eth1.

You should be able to do similar for the scsi controllers, since they
have different drivers and  specify something like
alias scsi0 LSImodule
alias scsi1 Adaptecmodule
or one of the other tricks using an install line in modprobe.conf to
make sure the LSI gets the driver loaded first and Linux sees it as

An install line on the order of:
"install <Adaptecmodule> modprobe <LSImodule> ; modprobe
--ignore-install <AdaptecModule>"
would install the LSI module before it installed the adaptec module even
if the adaptec is seen and tried to install first.

If this refuses to work you may have to do the LABEL thing and
reconfigure the fstab accordingly, but it should solve the problem..


> Jeff Vian wrote: 
> > On Sun, 2004-07-11 at 21:56, Naoki wrote:
> >   
> > > Hi all,
> > > 
> > >     I have a problem, when I install my OS ( FC2 ) on my nice machine 
> > > with an internal scsi controller my two disks are sda and sdb, which is 
> > > all nice and expected.  But then when I add a new scsi card and hook up 
> > > the external disk array the new array now becomes sda which has a very 
> > > negative effect, can't boot..
> > > 
> > > Any helpful hints?  I could label the disks sure but then swap is still 
> > > on sda2 and that's a problem.
> > > 
> > >     
> > The order of the scsi adapters being configured at boot time causes
> > that.... first adapter --> first device ==> sda.  AFAIK the easiest way
> > to fix that is to swap the positions on the mobo so the original adapter
> > is seen first.
> > 
> > BTW, by the time you labeled the partitions you could also change fstab
> > for swap as well as the filesystem partitions.  The real problem I would
> > see is the location of the grub boot image.
> > 
> > HTH
> > Jeff
> > 

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