On Thu, 14 Apr 2005, Laurent CARON wrote: > Hello, > > We are in the process of increasing the size our RAID Arrays as our > storage needs increase. > > I've got 2 solutions for this: > > - Copy the data over a new array and replace the disks Do this! You know it makes sense. If nothing else, it'll make sure you have an archive of the data. Do verify the copy before you replace the disks too. > - Replace each disk (one after the other(after resync)) of the existing > array with a bigger one. > > Start: > - Array is ok > - Remove 1 disk > - Array is degraded > - Add a bigger disk > - Resync > - Remove another disk > - Array is degraded > - Add a bigger disk > - Resync > ..... > > Would this be the 'state of the art' way ? You would have to guarantee that each disk had zero surface defects before you started this. Use badblocks (or dd) to do a surface scan of each disk. One bad block and you'll be in the 2-disk failure mode which will likely cause loss of all data. > Will the filesystem cope with it? Firstly, will the RAID cope with it, and my understanding is that it might not - initially. When you put in a new, bigger disk, it will only use the same number of blocks as the disk you are replacing it had. So after doing all the disks, the array size won't have changed! So next you'd need to look at the grow the array mechanism, and as I understand it, this is supported in the 2.6 kernel and mdadm, but the man page is short on examples, but I'm sure someone here might fill in the details. Then you'd have to grow the filesystem under it. > Is my mind completely broken? Well - not really, but IMO, doing it the individual disk swapping way is just too prone to errors and failure. I'd backup the data, replace the drives and restore it. And even if you do go down this route, I'd backup my data first anyway! (And then, since you have a backup, you have nothing to lose doing it the multiple disk swapping way, so write back and let us know if it worked :) Good luck! Gordon - 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
