Op vrijdag 01-05-2009 om 23:10 uur [tijdzone +0200], schreef Goswin von Brederlow: > Gabor Gombas <gombasg@xxxxxxxxx> writes: > > > On Wed, Apr 29, 2009 at 12:43:51PM +1200, Daniel Reurich wrote: > > > >> In which case your probably using a hardware raid controller anyway so > >> not our problem. Otherwise if the array is broken by a failed > >> controller we probably shouldn't boot of it anyway. > > > > I have set up a box with 8 SATA disks attached to 2 on-board > > controllers. The BIOS can boot from any of the controllers, but then it > > can only see the disks that are attached to the selected controller. > > Which is quite reasonable if the BIOS handles the controller selection > > by redirecting INT 13h (I have not checked). > > > > With "/" on RAID1, I can boot in any failure scenarios (I've actually > > tested that anno). With your setup, the box would never boot, since it > > could never access enough disks in a RAID5/6 array, even if all the > > disks/controllers are perfectly fine. > > So you have lost nothing. It doesn't boot now from raid5 (accross all > disks) and it still doesn't boot from raid5 with the proposal. Your > hardware just doesn't support it. > > >> What's specifically dangerous about it? Define the failure modes that > >> this scheme is unable to either cope with that it should do. > > > > There is no need for a failure mode. Your scheme does not work even when > > everything is fine. > > > > Gabor > > It would only be a problem if with the proposal things would get > worse. > It would get worse, as in many situations the installer would succeed, and the boot would fail. Many raid 5/6 configurations will spread over controllers, and not BIOS supports booting over several controllers. I really prefer the current situation, where you need to explicitly configure a RAID1. This makes clear what is happening, and reduces confusion. This propposal would make debug of a failed boot just so much more difficult. Cheers, Rudy -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
