Re: Fixed (hardisk) device names?

[Craig Sanders <cas@taz.net.au>]

On Wed, Mar 31, 2004 at 07:54:19AM +0200, Arnd Vehling wrote:
> does anyone know how to fix the device name on a debian linux
> system? For example. If i have two IDE hardisks, the devices will
> be named like this.
> 
> /dev/hda
> /dev/hdb
> 
> If i now must remove the first harddisk (/dev/hda) the second (/dev/hdb)
> will be renamed to (/dev/hda) after the reboot. As i want /dev/hdb to be
> a mirror of /dev/hda and used as failover disk _without_ opening the
> case and tampering with the IDE bus setup, i want linux to keep the name
> /dev/hdb for the drive no matter what happens.

huh?

that's EXACTLY what linux does for IDE drives.  the slave drive on the primary
IDE controller will *always* be /dev/hdb, regardless of whether there is a
master drive or not.

/dev/hda  - master drive on primary IDE controller
/dev/hdb  - slave drive on primary IDE controller
/dev/hdc  - master drive on secondary IDE controller
/dev/hdd  - slave drive on secondary IDE controller

> Is this possible?

it's standard.

> Another question. How can i copy two identical discs _including_ the boot
> block? "dd if=/dev/hda of=/dev/hdb" doesnt do it 

don't use dd for that.  set up a raid-1 mirror instead.  it's easy to do, only
about 5 minutes work.

also, for performance and safety, put your second drive on a separate IDE
controller.  that way it will still work even if one IDE controller fails.
e.g. have /dev/hda (primary IDE master) and /dev/hdc (secondary IDE master)
rather than /dev/hda & /dev/hdb.

> and there are no raw devices on linux AFAIK.

/dev/hd? ARE the raw devices.   

craig

-- 
craig sanders <cas@taz.net.au>

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