[CentOS] mdadm syntax

Tim Verhoeven tim.verhoeven.be at gmail.com
Fri Nov 2 20:22:17 UTC 2007

On Nov 2, 2007 8:14 PM, Art Baldini <rootajb at gmail.com> wrote:
> Hi All,
>     I am trying to create an MD device.  I am using the command:
> /sbin/mdadm --create --a /dev/md12 --level=1 --run --raid-devices=2
> /dev/sda12 /dev/sdb12
> to create the device, and to dynamically create the device file if needed.
> What I want is the device file to be created as /dev/md12, but with the -a
> flag it creates it as /dev/md<first unwsed minor number>.
> I have tried various options to the -a or --auto, but cannot seem to find
> the correct syntax.  From the man page it says:
>        -a, --auto{=no,yes,md,mdp,part,p}{NN}
>               Instruct mdadm to create the device file if needed, and to
> allocate an unused
>               minor number.  "yes" or "md" causes a non-partitionable  array
> to  be  used.
>               "mdp", "part" or "p" causes a partitionable array (2.6 and
> later) to be used.
>               The argumentment can also come immediately after "-a".  e.g.
> "-ap".
> Am I doing something wrong, or is there no way to get mdadm to automatically
> create a specific device file.

I've done it like this :

mdadm --create /dev/md12 --auto=yes --level=1 --run --raid-devices=2 /dev/...


Tim Verhoeven - tim.verhoeven.be at gmail.com - 0479 / 88 11 83

Hoping the problem  magically goes away  by ignoring it is the
"microsoft approach to programming" and should never be allowed.
(Linus Torvalds)

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