On Tue, May 04, 2010 at 04:09:09PM +0100, David Woodhouse wrote: > On Mon, 2010-05-03 at 22:02 +0200, Roy Sigurd Karlsbakk wrote: > > Is raid[56] coming to btrfs? There was some talk about it a year back > > or so, but I haven't seen anything yet.... > > Um, there was some talk about it about four days ago. You even > participated in that thread! > > As it stands, it has the traditional 'write hole' problem -- when you > overwrite _part_ of a stripe, you have to update the parity block(s) too > and you have a short period of time where the parity doesn't match the > actual data. If you get a crash followed by a disk failure during that > period of time, you get data loss. > > The solution is always to write a full stripe (across all the disks in > the set). Chris said he'd sort that out in the upper layers of btrfs, > about which I know little. We've been waiting a while for that. Yeah, I've got it nailed down for data and metadata here, and I'm integrating all these development patches into one branch (O_DIRECT etc, raid, zheng's work). -chris -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
