>>>> Also, if you want two rotating backups I would create two stacked raid1s. >>>> >>>> mdadm -C /dev/md0 -l1 -n2 -b internal /dev/main-device /dev/first-backup >>>> mdadm -C /dev/md1 -l1 -n2 -b internal /dev/md0 /dev/second-backup >>>> mkfs -j /dev/md1 On Feb 7, 2011, at 5:19 PM, NeilBrown wrote: > I'm surprised that you found the correct advise, and chose not to follow > it ..... Thanks again for your advice. I didn't search the list until after completing my initial setup; my mistake and my lesson learned: research first. > The array you will end up installing on is (slightly) smaller than than the > array you have created. So no: you cannot re-arrange things - you have to > start again. > > > (well, to be honest, it is possible that you could resize whatever is on the > array and then build the secondary array and make it work. But that path is > error-prone and this margin is not large enough to properly describe the > process). Reckless fool that I am, I'm going to try it anyway. Here's my rough plan: 1. Degrade the 3-disk raid1 array by removing two disks, leaving only one, and leaving the array running. 2. Set up the first 2-disk array (md0 in your description) de novo on the two freed disks 3. Move my data from the original raid1 array (with only 1 of three disks present) to the new 2-disk md0 via lvm mirroring 4. Free the third disk by finally taking down the original raid1 array 5. create the second 2-device array (md1) using md0 and the freed third disk. Somehow ensure that the md0 component has primacy for syncing. Jeff -- 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
