On Wed, 2014-01-01 at 23:33 +1300, Pieter De Wit wrote: > On 1/01/2014 17:54, Krzysztof Adamski wrote: > > On Wed, 2014-01-01 at 14:02 +1300, Pieter De Wit wrote: > >> On 1/01/2014 13:51, Krzysztof Adamski wrote: > >>> <snip> > >> Hi, > >> > >> RAID Level 6 requires a minimum of 4 drives to implement > >> > >> Cheers, > >> > >> Pieter > > I have seen messages by Neil from 2011 that he was planning to remove > > this silly minimum requirement of 4 drive for RAID6. > > > > > IMHO, that "silly minimum requirement" *is* RAID6, 2xDATA, 2xPARITY. If > you make it 1 DATA, then you might as well have RAID1 with a hot spare > (not even sure how the calc's will work - for RAID6 like that, RAID1 is > easy :) ) Based of what you are saying you probably would not believe that RAID5 can be made with 2 drives, DATA + 1 PARITY. But Linux RAID supports that just fine (thanks Neil). Hot spares are a joke, you have to wait for a drive to fail before you use them, that can be to late. A 3 drive RAID1 make more sense. On one system I have a 8 drive RAID1 (the /boot partition) the / (root) partition is a 8 drive RAID6. > I would use RAID5 for now, then migrate to RAID6 when you get a forth > drive. IIRC, you can always upgrade "up", not down (RAID numbers that is) Using RAID5 defeats the purpose of having 2 parity drives. If you want to know why I'm so paranoid, if that I had 5 enterprise series drives fail within a month period of each other. I didn't lose any data, but from now I don't trust any drive and I expect triple redundancy. > Cheers, > > Pieter > -- > 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 -- 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
