I thought that I would post an update to this thread as I now have a
better understanding of what is going on. It seems that the old Linux
IDE driver was broken and failed to respect the HPA. This was fixed in
the new libata driver, but because a system that had been installed
under an old kernel would no longer work properly with the new driver
since it could not access the entire disk, Ubuntu decided to disable the
HPA by default. Since the bios and windows respect the HPA, and Ubuntu
Linux does not, that lead to the dmraid problem. The workaround is to
set the libata parameter directing the kernel to respect the HPA. The
vanilla kernel respects it by default, so this should not be an issue
for non Ubuntu users.
Phillip Susi wrote:
It appears to be related to the use of a Host Protected Area ( HPA ).
Both disks are the same size, but one has some space reserved as an HPA.
The metadata in that disk reports its size as reduced by the size of
the HPA. The metadata in the second disk appears to report the size of
the first disk in its entirety, not respecting the HPA. Because the
metadata on each disk disagrees, their checksums were different when
created which lead to them showing different values for family_num,
which causes dmraid to identify each disk as belonging to different
unrelated raid sets.
So it appears that the bios has a bug that caused it to generate
incorrect metadata when the raid set was created, yet the windows driver
appears to ignore this inconsistency and operate anyhow.
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