[Discuss] How do you backup "/" with rsync?

[Alan W. Irwin]

On 2007-12-11 19:07-0800 Steven Kurylo wrote:

> Its quite possible for the BIOS to see the internal drive as the first
> boot device, which then loads grub.  Grub loads the menu.lst and then
> the kernel from the internal drive.  Once the kernel is running, it
> could then load eSata controller, making the external drive sda, then
> load the ICH9 controller, making the internal drive sdb.  Then once
> the kernel starts mounting your fstab, it uses the sda like you've
> specified - but sda is the external drive.
>
> That would explain what you saw.

I think you must be right.  That grub menu refers to hd0 and hd1 but at grub
time the kernel is not loaded yet so hd[01] must correspond to the BIOS idea
of what are the first and second disk devices, and not the kernel's idea of
what are the first and second disk devices.  This conclusion seems to be
confirmed by
http://blogs.sun.com/jerrysblog/entry/svm_root_mirroring_and_grub where he
refers to the BIOS's idea of drive order when considering grub's disk order.
Presumably, there must be a more official grub reference on this question,
but I cannot find it.

It sure complicates Linux life when the BIOS and grub sometimes have a
different disk order convention than the Linux kernel, but I guess we are
stuck with this complication (at least until all MB manufacturers go with
LinuxBIOS rather than proprietary BIOS's).

Alan
__________________________
Alan W. Irwin

Astronomical research affiliation with Department of Physics and Astronomy,
University of Victoria (astrowww.phys.uvic.ca).

Programming affiliations with the FreeEOS equation-of-state implementation
for stellar interiors (freeeos.sf.net); PLplot scientific plotting software
package (plplot.org); the libLASi project (unifont.org/lasi); the Loads of
Linux Links project (loll.sf.net); and the Linux Brochure Project
(lbproject.sf.net).
__________________________

Linux-powered Science
__________________________