dmraid failure/test cases [fc5-7]

[Sean Bruno]

I spent some time trying to arm wrestle my machines fake raid
controllers(ck804, sil 3118) and a pci board I had lying around(adaptec
1210sa), and came to the conclusion that dmraid was causing me serious
grief.

First off, I could _not_ get dmraid to go away during the install on
x86_64.  Even the nodmraid kernel option failed me.  Each time I booted
up with two disks connected to any controller, the only drive I had at
my disposal was /dev/mapper/mapper0.  I did notice that there was a
'disable dmraid' toggle in the advanced setup button in the installer,
however this option was grayed out in all situations that I could come
up with.

Second, all three of the SATA raid controllers I tested failed in
similar, yet different ways during the install process.  They mainly
failed during file system creation, but there was some variances in
behavior that were interesting.  For example, some would cause anaconda
to dump and crash, others would simply cause the installer to abort and
reboot the machine.

Third, and the most annoying, was that I couldn't install a plain s/w
raid configuration with 2 drives connected.  There was just no way to
keep the system from assuming that I meant to use /dev/mapper/mapper0
even after I ensured that the superblock metadata was wiped out with a
quick call to 'dmraid -Er /dev/sdX' to be sure that it was really gone.

In a related note, it would be nice if the installer would allow you to
create a broken raid 1 in the installer, anaconda should definitely warn
you and tell you that what you are doing is loopy, but there should be a
way to just say, "go ahead if you really wanna".  I was unable to find
this magic, and had to install on a single drive.  I guess I'll have to
migrate to s/w raid after the install is finished.

I am more than interested now in diagnosing and fixing the issues I've
spewed forth here.  I've even gone so far as to start some bugzilla
goodness on tkt:246817 

Any takers in dev land want to give me a hand with this one?

Sean