Hello, md with v1 superblocks seem to somehow associate device slots with specific devices and doesn't re-use them with others (this was already reported by John Hughes a while ago, btw.). So, my question is: how can I force md to finally give up a specific slot or re-use it with another device? For example, creating a degraded array reserves slot 1 for the "missing" device and never re-uses it, but uses slot 2 instead: # mdadm -C -n 2 -l raid1 -a md /dev/md9 /dev/loop0 missing # mdadm -a /dev/md9 /dev/loop1 md9 : active raid1 loop1[2] loop0[0] Creating the array fully developed uses slot 0 and 1 as expected: # mdadm -C -n 2 -l raid1 -a md /dev/md9 /dev/loop0 /dev/loop1 md9 : active raid1 loop1[1] loop0[0] The only way I found to enforce using slot 0 and 1 while creating a degraded array is to grow the number of active devices later: # mdadm -C -n 1 --force -l raid1 -a md /dev/md9 /dev/loop0 # mdadm -a /dev/md9 /dev/loop1 # mdadm -G -n 2 /dev/md9 md9 : active raid1 loop1[1] loop0[0] Unfortunately, the reverse assumption: reduce the number of active devices to re-claim unused slots doesn't appear to work: # mdadm -C -n 2 -l raid1 -a md /dev/md9 /dev/loop0 missing # mdadm -a /dev/md9 /dev/loop1 md9 : active raid1 loop1[2] loop0[0] # mdadm --fail /dev/md9 /dev/loop1 # mdadm --remove /dev/md9 /dev/loop1 # mdadm -G -n 1 --force /dev/md9 # mdadm -a /dev/md9 /dev/loop1 # mdadm -G -n 2 /dev/md9 md9 : active raid1 loop1[2] loop0[0] I'm using Debians mdadm 3.1.2-2 which defaults to v1.2 superblocks. regards Mario -- Tower: "Say fuelstate." Pilot: "Fuelstate." Tower: "Say again." Pilot: "Again." Tower: "Arghl, give me your fuel!" Pilot: "Sorry, need it by myself..." -- 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
