On Sat, 2006-03-11 at 16:31 -0800, dean gaudet wrote: > On Sat, 11 Mar 2006, Ming Zhang wrote: > > > On Sat, 2006-03-11 at 16:15 -0800, dean gaudet wrote: > > > > > you're planning to do this while the array is online? that's not safe... > > > unless it's a read-only array... > > > > what i plan to do is to pull out the disk (which is ok now but going to > > die), so raid5 will degrade with 1 disk fail and no spare disk here, > > then do ddresue to a new disk which will have same uuid and everything, > > then put it back, then bitmap will shine here right? > > > > so raid5 is still online while that disk is not part of raid5 now. and > > no diskio on it at all. so do not think i need an atomic operation here. > > if you fail the disk from the array, or boot without the failing disk, > then the event counter in the other superblocks will be updated... and the > removed/failed disk will no longer be considered an up to date > component... so after doing the ddrescue you'd need to reassemble the > raid5. i'm not sure you can convince md to use the bitmap in this case -- > i'm just not familiar enough with it. i am little confused here. then what the purpose of that bitmap for? is not that bitmap is for a component temporarily out of place and thus out of sync a bit? > > > this raid5 over raid1 way sounds interesting. worthy trying. > > let us know how it goes :) i've considered doing this a few times > myself... but i've been too conservative and just taken the system down to > single user to do the ddrescue with the raid offline entirely. sure. after we finish this discussion and sort out a stable plan. do not want to risk my data. :P > > -dean - 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
