NeilBrown [off-list ref] writes:

On Mon, 27 Oct 2014 10:18:47 -0400 micah anderson [off-list ref] wrote:

quoted

Hi,

i've got a raid1 setup, where one drive died, it was replaced with a new
one, but its stuck in a (S) state and I can't seem to get it added into
the array, /proc/mdstat looks like this:

md3 : active raid1 sdc1[2](S) sdd1[1]
      976759672 blocks super 1.2 [2/1] [_U]

where sdc1 is the replaced drive.

What is the right way to get this added back?

I've a feeling this bug might have been fixed.
What versions of mdadm and Linux are you using?

I'm using squeeze here, and had 3.1.4-1+8efb9d1+squeeze1 installed, I
just installed the backport, which is 3.2.5-3~bpo60+1.

Are there any errors in the kernel logs when you --add the device?

After installing the backported 3.2.5, I tried to add it, and it said:

# mdadm --add /dev/md3 /dev/sdc1
mdadm: Cannot open /dev/sdc1: Device or resource busy

so I did a --remove of the drive, and then added it, it then proceeded
to sync the array, and after that finished, it is now back in the (S)
state.

Can I just zero the superblock of that device and re-add it in order to
resolve this?

thanks!
micah