On Thu, Feb 12, 2009 at 08:21:12PM +1100, NeilBrown wrote: > On Thu, February 12, 2009 7:11 pm, Keld Jørn Simonsen wrote: > > On Thu, Feb 12, 2009 at 02:10:10PM +1100, NeilBrown wrote: > >> Comments and testing very welcome. > > > > I would rather have functionality to convert raid10 to raid5. > > raid1 should be depreciated, as raid10,n2 for all purposes is the same > > but better implementation and performance, and raid10,f2 and raid10,o2 > > are even better. Nobody should use raid1 anymore. > > That is a fairly simplistic view. It was also formulated to provoke some thoughts. > raid1 supports --write-mostly and --write-behind which raid10 is unlikely > ever to support. why? Anyway would it not be possible that this functionality be implemented for raid10,n2? > Certainly in many cases raid10 is just as good or better than raid1 > though. > > Certainly a raid10->raid5 conversion for a 2-drive n2 configuration > is trivial to arrange. Other conversions are less likely to be supported > as they require significant non-trivial rearrangement of data. Yes, possibly. Some code to grow raid10 would also be desirable. Maybe it is some of the same operations that need to be applied: getting the old data in, have it restructured for the new format, in a safe way, and possibly with the help of an extra disk, or possibly not. It sounds non-trivial to me too. Best regards keld -- 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
