DANGER!!! Problems with 10.04 installer (RAID devices *will* get corrupted)

[Andrew Farris]

On Thu, 2010-04-22 at 14:50 +0800, Christopher Chan wrote:
> > Please, tell me you understand now.
> >
> 
> Oh I understand that the installer is messing up stuff but people here 
> are saying that nah, it's a borky fakeraid controller you have because 
> of the #191119 link.

I still don't buy the 'it's a fakeRAID controller problem'
explanation... it feels too much like a cop-out answer when its fairly
obvious (to me anyway) that the problem doesn't lie in the raid
controller, but the installer, regardless of any 'oh this controller
isn't open' issues. 

Also, as far as I understand the issue, even if the controller driver
implements some sort of proprietary BS in order to control the array on
windows, and doesn't on linux, the windows installer is STILL smart
enough to not write changes to the raid array, if you tell it not to
write the changes. It's also still smart enough to actually tell that
it's a RAID array during installation, before this 'proprietary driver'
has been loaded, making the issue moot for most usage cases (I say most
because I'm aware that it's sometimes necessary to load a custom raid
driver before starting the installation).

All other issues aside, the issue here seems (to me at least) be an
issue with the installer detecting what these partitions 'used to be'
rather than 'what they are' and therefore is mis-handling them...and
this is un-undeniably a fault in the installer... and possibly the
partitioning tools for leaving this information intact in the first
place (Why is this even done? If somebody can tell me, I'd be most
appreciative.)

The reason I believe this 'leftover' partition data is root cause is
because a friend of mine had an eerily similar issue, except that he had
some drives in a RAID array, and decided to dump the RAID in favor of
rsync backups instead. His issues began after reinstalling, because
after wiping the partitions, and setting them up as 2 separate disks
(removing all references to them being a soft-RAID device) upon booting
into his new install, the boot failed because Ubuntu was still trying
treat the drives as a RAID device. His solution was basically to
manually edit bits in the partition table and removing the old entry
indicating that the disk was in a RAID array... even though he got it
fixed, this step was completely unnecessary, and was clearly not an
issue with the RAID controller, but a fault in the installer's handling
of RAID.

So, the 'common denominator' here is the
'this-partition-used-to-be-a-*' nonsense that is recorded in the
partition table for some unconceivable reason, and how the installer
handles that data. Surely there is a better way?

-- 
Andrew
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