On Wed, 29 Oct 2014 10:03:16 -0400 micah [off-list ref] wrote:

NeilBrown [off-list ref] writes:

quoted

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.

Is assume that is the version of mdadm.  You didn't say what version of Linux.

quoted

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

You didn't answer this question either.  Are there any messages in the
kernel log: /var/log/kern.log on debian.
Or in the output of "dmesg".

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?

If it resyncs and the is still spare, there was almost certainly some sort of
failure.  There really must be something in the kernel logs at that time.

NeilBrown