17

I am having trouble going from a single disk to raid 10

The command issued is:

mdadm --create /dev/md0 --level=10 --raid-devices=8 /dev/sd[abcdefgh]1

The output is:

mdadm mdadm: cannot open /dev/sda1: Device or resource busy

I have verified this has nothing to do with DM:

]# dmsetup status

No devices found

The file system is GPT, I used sgdisk --backup=table /dev/sda followed by sgdisk --load-backup=table /dev/sdb through to sdh to copy the partitions table

The table looks like:

Number  Start   End     Size    File system     Name  Flags
 1      1049kB  525MB   524MB   ext3                  boot
 2      525MB   86.4GB  85.9GB  ext4
 3      86.4GB  90.7GB  4295MB  linux-swap(v1)
 4      90.7GB  1000GB  909GB

I have created the other arrays fine however I cannot create the raid for the 1st and 2nd partition.

current status:

]# cat /proc/mdstat
Personalities : [raid10]
md3 : active raid10 sdh3[7] sdg3[6] sdf3[5] sde3[4] sdd3[3] sdc3[2] sdb3[1] sda3[0]
      16766976 blocks super 1.2 512K chunks 2 near-copies [8/8] [UUUUUUUU]
        resync=DELAYED

md4 : active raid10 sdh4[7] sdg4[6] sdf4[5] sde4[4] sdd4[3] sdc4[2] sdb4[1] sda4[0]
      3552147456 blocks super 1.2 512K chunks 2 near-copies [8/8] [UUUUUUUU]
      [========>............]  resync = 42.5% (1513033344/3552147456) finish=76.2min speed=445722K/sec


unused devices: <none>

Can anyone offer any advice, do I need to boot in to a rescue disk and create the arrays for / and /boot while they are not mounted?

Matt Popovich
  • 103
Backtogeek
  • 607

4 Answers4

12

Just try to stop before reassambling array :

sudo mdadm -Esv
sudo mdadm  --stop /dev/md*
sudo mdadm --misc --scan --detail /dev/md0
sudo mdadm -v --assemble "$array" "$disk1$part" "$disk2$part"
rzr
  • 269
5

do I need to...create the arrays for / and /boot while they are not mounted?

Precisely.

I hope you also realised that the old contents will be wiped in the process, so you might want to create a new array with one device missing (use mdadm --level=10 --raid-devices=8 --missing /dev/sdb1 /dev/sdc1 /dev/sdd1 /dev/sde1 /dev/sdf1 /dev/sdg1 /dev/sdh1). Then format the filesystem on the new array volume and copy all data from /dev/sda1 to it. Then reboot from the array (thus NOT using the /dev/sda1 root) and actually add /dev/sda1.

Do not forget to adjust the bootloader accordingly.

Hennes
  • 4,852
2

I had the same issue. Replaced a faulty drive (after failing and removing from RAID 1), but then could not add it back. Was getting resource busy all the time.

SOLVED AS FOLLOWS...

The problem was that the system had mapped my new disk as md126 and md127 (not sure why). So I had these two extra drives showing up unconnected, but present in cat /proc/mdstat.

When I did mdadm --stop /dev/md*, it removed the md126 and md127 entries. Then the resource in use error went away and when I did the mdadmin --manage /dev/md0 --add /dev/sdb1 it was working. Yay :-)

Robert B
  • 21
0

First open this file /proc/mdstat and check if your block device /dev/sda1 is part of any md* if you see it there try to remove it using : mdadm --stop md* (* means the number after md that /dev/sda belong to )

arif
  • 1
  • 1