Devices numbering [Was Re: Switch from legacy ata(4) to CAM-based ATA]

[Arnaud Lacombe]

Hi,

On Thu, Apr 21, 2011 at 1:31 PM, Garrett Cooper <yanegomi at gmail.com> wrote:
> Although this may not be a list of fixable issues, here are some observations (in part with the new geom raid infrastructure):
> 1. Channels are no longer fixed of course because ata uses cam now, and I believe that device numbering is done based on probe ordering. This is fun to work with when dealing with appliances or configurations that require deterministic probe and mount, especially when drives fail, go missing, etc, but can be hacked around in device.hints. This is why it would be nice for geom labels to work in a sane manner.
Out of context, but the same issue appear with network interfaces. If
you're got 6 networks interface and the 3rd chip die, the 3 last get a
bad numbering. I am not sure it is fixable by any device.hints.

The Linux' world has the same issue (well, worse actually, as all
interfaces uses the same 'eth' name). RedHat has been/will be
introducing "Consistent Network Device Naming"[0,1] in Fedora 15,
which may be an interesting move.

 - Arnaud

[0]: http://domsch.com/linux/lpc2010/lpc2010-network-device-naming.pdf
[1]: http://domsch.com/blog/?p=455