On Tue, Nov 15, 2011 at 09:33:14AM -0500, Phillip Susi wrote: > On 11/15/2011 4:22 AM, Ilya Dryomov wrote: > >Restriper won't let you do raid1 -> dup transition because dup is only > >allowed for a single-spindle FS, so you'll end up with error "btrfs: > >unable to start restripe ...". > > > >There is no way to prioritize disks during restripe. To get dup back > >you'll have to convert everything to single, remove the second drive and > >then convert metadata from single to dup. > > So there is no way to put a disk into read only mode and prevent > allocations of new chunks there? > > It seems like both of these limitations are highly undesirable when > trying to recover from a failing disk. You don't want any more data > being written to the failing disk while you are trying to remove it, > and you certainly don't want to drop back to a single copy of data > that is then written to the failing disk.
If you have a failing disk in a raid setup, you don't need to downgrade your raid, you can add a third drive and remove the failing one. But that's inconvenient and most of the time you'll have to do a full balance. So another thing I'm working on is drive swap, when it's done it will take care of the failing disk scenario. If you have a raid setup and one of the disks gone bad you'll be able to say btrfs device replace FAILED NEW <mountpoint> and it will put valid copy onto the fresh drive, basically doing a raid rebuild. Thanks, Ilya -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html