From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave W Subject: How do I determine which drive should be in which slot? Date: Sat, 26 Jun 2010 05:32:08 +0000 (UTC) Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Return-path: Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids After making some changes in the bios to my boot order, my 5-drive RAID6 stopped assembling. Three of the five known-good drives suddenly stopped getting added to the right slots. There are no disk errors in the logs and I can read from the drives with no problems. # mdadm --stop /dev/md0 mdadm: stopped /dev/md0 # mdadm -v -Af /dev/md0 /dev/sd[bcdef]1 mdadm: looking for devices for /dev/md0 mdadm: /dev/sdb1 is identified as a member of /dev/md0, slot 7. mdadm: /dev/sdc1 is identified as a member of /dev/md0, slot 6. mdadm: /dev/sdd1 is identified as a member of /dev/md0, slot 2. mdadm: /dev/sde1 is identified as a member of /dev/md0, slot 3. mdadm: /dev/sdf1 is identified as a member of /dev/md0, slot 5. mdadm: no uptodate device for slot 0 of /dev/md0 mdadm: no uptodate device for slot 1 of /dev/md0 mdadm: added /dev/sde1 to /dev/md0 as 3 mdadm: no uptodate device for slot 4 of /dev/md0 mdadm: added /dev/sdf1 to /dev/md0 as 5 mdadm: added /dev/sdc1 to /dev/md0 as 6 mdadm: added /dev/sdb1 to /dev/md0 as 7 mdadm: added /dev/sdd1 to /dev/md0 as 2 mdadm: /dev/md0 assembled from 2 drives and 3 spares - not enough to start the array. # Reading the thread at http://thread.gmane.org/gmane.linux.raid/17774, I think that a command like this: mdadm -C /dev/md0 -l6 -n5 /dev/sd[bcdef]1 would tell mdadm to rewrite the superblock with the disks in the right slots. Does the order on the command line determine the slot allocations? How can I tell that my disks will get put in the right slots? Is it safe to just try this order? Thanks, Dave