On Wed, May 24, 2017 at 12:12:32PM +1000, NeilBrown wrote: > What does work is: > # start with a degraded array, device 0 missing > mdadm --grow /dev/md42 --array-size=..... > echo frozen > /sys/block/md42/md/sync_action > mdadm /dev/md42 --add /dev/loop0 > echo 0 > /sys/block/md42/md/dev-loop0/slot > mdadm --grow /dev/md42 --backup-file=... --raid-devices=4 Wow. Thanks. This should merge Step 1+2, but not Step 3, right? I really need to take a closer look at the things in /sys/.../md/... Seems like you can do great things with it... terrible, yes, but great. ( Step 3 would be turning slot 4 to-be-spare into slot 0, without --add ing another device at all. That's what would happen if /dev/loop0 was actually backed by and thus identical with the slot4 device. But that's playing dirty. ) Regards Andreas Klauer -- 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
