Hi Roger & Mikael, Thanks a lot for your replies. I tried the following and still to no avail. Here are the results of the various commands: # cat /proc/mdstat Personalities : md0 : inactive sda2[0](S) sdb1[4](S) sdc2[1](S) 480215144 blocks super 1.2 unused devices: <none> # mdadm -V mdadm - v3.2.6 - 25th October 2012 # uname -a Linux triveni 3.10.6-2-ARCH #1 SMP PREEMPT Tue Aug 13 09:47:01 CEST 2013 x86_64 GNU/Linux # mdadm -Esv ARRAY /dev/md/0 level=raid5 metadata=1.2 num-devices=4 UUID=01b153ea:a93c7325:c13bf9cf:3195666f name=sysresccd:0 devices=/dev/sdc2,/dev/sdb1,/dev/sda2 Based on Roger's mail, set the kernel option "md_mod.start_dirty_degraded=1": # cat /proc/cmdline BOOT_IMAGE=/vmlinuz-linux root=/dev/mapper/triveni--lvm--320gp3-root rw md_mod.start_dirty_degraded=1 Still, I get: # mdadm -Avfs mdadm: looking for devices for /dev/md0 mdadm: no RAID superblock on /dev/dm-6 mdadm: no RAID superblock on /dev/dm-5 mdadm: no RAID superblock on /dev/dm-4 mdadm: no RAID superblock on /dev/dm-3 mdadm: no RAID superblock on /dev/dm-2 mdadm: no RAID superblock on /dev/dm-1 mdadm: no RAID superblock on /dev/dm-0 mdadm: /dev/sdc2 is busy - skipping mdadm: no RAID superblock on /dev/sdc1 mdadm: no RAID superblock on /dev/sdc mdadm: /dev/sdb1 is busy - skipping mdadm: no RAID superblock on /dev/sdb mdadm: no RAID superblock on /dev/sda3 mdadm: /dev/sda2 is busy - skipping mdadm: no RAID superblock on /dev/sda1 mdadm: no RAID superblock on /dev/sda On 21-Sep-13 1:44 PM, Roger Heflin wrote: > cat /proc/mdstat > > It is probably already partially assembled (and since no force not > active--note there is a kernel optionmd_mod.start_dirty_degraded=1 > that will enable if the array can at least work ) so not operational, > typically you can stop it and it will no longer show up in mdstat then > you can do what you are trying to do. > > lsof will not show things that are being held open/busy in the kernel, > lsof only shows userspace useage. > > On Sat, Sep 21, 2013 at 9:32 AM, Sachin Garg > <sgarg.bugreporter@xxxxxxxxx> wrote: >> Hi, >> >> I am on Arch Linux. I have a 4 device RAID 5 of which 1 device is no longer >> working. I am unable to assemble the raid. >> >> The active devices are:/dev/sda2, /dev/sdb1, /dev/sdc2 >> >> The errors I get are like: >> >> # mdadm -Avf /dev/md127 >> mdadm: looking for devices for /dev/md127 >> mdadm: no RAID superblock on /dev/dm-6 >> mdadm: no RAID superblock on /dev/dm-5 >> mdadm: no RAID superblock on /dev/dm-4 >> mdadm: no RAID superblock on /dev/dm-3 >> mdadm: no RAID superblock on /dev/dm-2 >> mdadm: no RAID superblock on /dev/dm-1 >> mdadm: no RAID superblock on /dev/dm-0 >> mdadm: /dev/sdc2 is busy - skipping >> mdadm: no RAID superblock on /dev/sdc1 >> mdadm: no RAID superblock on /dev/sdc >> mdadm: /dev/sdb1 is busy - skipping >> mdadm: no RAID superblock on /dev/sdb >> mdadm: no RAID superblock on /dev/sda3 >> mdadm: /dev/sda2 is busy - skipping >> mdadm: no RAID superblock on /dev/sda1 >> mdadm: no RAID superblock on /dev/sda >> >> I would like to know what is making these devices busy. I do not see any >> indication from lsof or from the device mapper that these devices are being >> used. I have even changed the initramfs and the fstab etc. to prevent this >> array from being started at boot time - still unable to assemble it. >> >> This array contains my /home and I do not know how to recover it. >> >> Help please ... >> >> Thanks, >> Sachin >> -- >> 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 -- 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