On Tue, 14 Nov 2006, Will Sheffler wrote: > Hi. > > What is the safest way to switch out a disk in a software raid array created > with mdadm? I'm not talking about replacing a failed disk, I want to take a > healthy disk in the array and swap it for another physical disk. Specifically, > I have an array made up of 10 250gb software-raid partitions on 8 300gb disks > and 2 250gb disks, plus a hot spare. I want to switch the 250s to new 300gb > disks so everything matches. Is there a way to do this without risking a > rebuild? I can't back everything up, so I want to be as risk-free as possible. > > I guess what I want is to do something like this: > > (1) Unmount the array > (2) Un-create the array > (3) Somehow exactly duplicate partition X to a partition Y on a new disk > (4) Re-create array with X gone and Y in it's place > (5) Check if the array is OK without changing/activating it > (6) If there is a problem, switch from Y back to X and have it as though > nothing changed > > The part I'm worried about is (3), as I've tried duplicating partition images > before and it never works right. Is there a way to do this with mdadm? if you have a recent enough kernel (2.6.15 i think) and recent enough mdadm (2.2.x i think) you can do this all online without losing redundancy for more than a few seconds... i placed a copy of instructions and further discussions of what types of problems this method has here: http://arctic.org/~dean/proactive-raid5-disk-replacement.txt it's actually perfect for your situation. -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
