On Tue, Feb 17, 2015 at 9:19 PM, William Park <opengeometry@yahoo.ca> wrote:
Disk failed last September, and you're replacing it now?  Boy, you got
balls!

You are better off to use whatever utility you used in the first place.
Manual typing would go something like
    man mdadm
    cat /proc/mdstat

understand above commands
 
    mdadm -D -v /dev/md0

what does this command do/mean?
 
    mdadm /dev/md0 --add /dev/sdx

(I understand I will need a different letter instead of the x)
what does this command do/mean?
 
where
    /dev/sdx is the new disk.  Here, the new device should be the "same"
    as the old.  If the old was a partition (eg. /dev/sda1), then the
    new should be a partition.  If the old was entire device (eg.
    /dev/sda), then the new should be entire device also.
--
I am not asking the questions to be confrontational just have learned that typing in
commands the results of which you do not know or the effect you do not know/understand
can have large effects.

(In the past I have too often totally borked my system and I really don't want to take two
weeks from my life and spend all day trying to reestablish things.)

Thanking you for your interest and assistance!

Dee
 
William


On Tue, Feb 17, 2015 at 03:42:07PM -0600, o1bigtenor wrote:
> Greetings
>
> I have been running a raid 10 array for almost 3 years.
>
> Last September on a reboot (forced by Firefox and kernel memory interaction
> problems) came up with one of the drives being listed as DOA.
> The raid array has continued to run on 3 drives although on reboots there
> is much complaining from whatever in the boot up process.
> I had the replacement drive sent to me and today I installed the drive.
>
> I was under the assumption that the raid array would rebuild itself upon
> startup with a new drive (4th out of 4).
>
> This did not happen.
>
> I am running Debian Jessie (testing) and have the whole time in question.
> I can mount the array and it is visible.
> I'm looking at backing up the array (on blu-ray discs) but as I'm now to
> circa 45 GB of data and I was at about 22 GB when I last did a backup this
> is going to be a momentous event.
>
> How do I ask mdadm to include this new drive into the array? (Without
> borking everything!! I have found lots of instructions on how to create but
> none in an hour of trying different search phrases on how to rebuild or how
> to cause the array to rebuild itself. I have only been able to find
> instructions for when the array is totally sick and I'm not there (yet - -
> - grin!) but I don't want to wait until another drive craps out to get
> things going.)
>
> TIA
>
> Dee