Re: (i386) Changing the order of "wd"s

[Louis Guillaume <louis%zabrico.com@localhost>]

Ingolf Steinbach wrote:
> Hi,
>
> in my PC, I have an old hard disk attached to the on-board IDE
> controller and a newer SATA disk attached to a separate controller in
> one of the PCI slots.
>
> As I plan to retire the old disk soon and work only with the SATA
> disk, I'd prefer to have the SATA disk as wd0 and the old one as wd1
> in order to keep the numbering consistent when the old one will be
> gone.
>
> If I disconnect the old disk, the new disk is handled as wd0 during
> installation of NetBSD (5.0.1) to that disk. But when I connect the
> old disk again (to copy the data), the new disk is then attached as
> wd1 which causes the boot procedure to fail.
>
> How can I specify the numbering (except building a custom kernel with
> hard-wired numbers)?
>
> Kind regards
> Ingolf

As noted by others there really isn't a way to switch the drive device 
numbering without doing it in the kernel. The way I usually handle this 
is to update /etc/fstab with the appropriate devices for the disk based 
on the current situation. The course of action I would take is this:

 o Connect both drives
 o Boot off the "new" disk to single user mode ( boot -s )
 o mount -uw /
 o fix /etc/fstab ( s/wd0/wd1/ )
 o mount -a
 o mount /dev/wd0x to /somewhere
 o copy data as needed
 o fix fstab again ( s/wd1/wd0 )
 o reboot

... beats building a special kernel just for an old disk.

Louis