nice :) i never read about it on raid 10, maybe i could use, thanks! 2011/1/26 David Brown <david@xxxxxxxxxxxxxxx>: > On 25/01/2011 19:56, Roberto Spadim wrote: >> >> hi guys... i have a damaged disk... >> iæ using raid1 >> the computer crashed with the floor :P hihiih sorry, but the disks are >> damaged at the same position >> check: http://www.spadim.com.br/hd%20agra.zip >> the problem: since raid1 (mirror) is done with real mirror, the disk >> position are the same... >> if i was using a mirror but on disk 1 i write from beggining to end, >> and disk 2 from end to beggining , i donæ crash the disk at the same >> position, for disk 1 i crash it some bytes, for disk 2 i crash some >> others bytes, since beggining is a small cilinder and end a bigger, i >> could loose less information than mirror >> could we implement a 'inverted' mirror? just for hard disks (for ssd >> itæ a small loss of cpu/memory) >> thanks >> > > If you are worried about the disks being in the same position, then I assume > you mean the heads were in the same position when they crashed into the > disk. ÂIf that's the case, then it doesn't really matter too much if the > same bytes on the disk were hit - your disks are trashed anyway, and you'll > need expensive professional recovery services to deal with it. > > If you are not talking about head crashes, and merely about corruption > because the disks were being written to in the same place on both disks, > then the layout on the disk will make little difference - the same data will > be written to the same logical place at roughly the same time. ÂIt doesn't > matter where this data is located physically on the disk, since it is the > data that matters. ÂThe same thing actually applies to head crashes too. > > If you really want an "inverted" mirror, there is an easy way to get much of > the same effect. ÂInstead of setting up raid1, use raid10 with "far 2" > positioning. ÂThe effect is roughly like this: > > disk1 (stripe 1) (mirror of stripe 2) > disk2 (stripe 2) (mirror of stripe 1) > > So the two copies of the data are in different physical positions on each > disk. ÂIt's not a full reversal, but you can think of disk 2 as being split > in two and its two halves swapped. > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-raid" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at Âhttp://vger.kernel.org/majordomo-info.html > -- Roberto Spadim Spadim Technology / SPAEmpresarial -- 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
