mdadm: SET_ARRAY_INFO failed for /dev/md0: File exists

mdadm: SET_ARRAY_INFO failed for /dev/md0: File exists

[me]

Hi,

I did a fresh install of Sarge, updated the kernel to 2.4.26.  then did:

platinum:~#  mdadm -C /dev/md0 --level raid1 --raid-disks 2 missing
/dev/hdc1
mdadm: /dev/hdc1 appears to contain an ext2fs file system
    size=117218240K  mtime=Wed Dec 31 18:00:00 1969
Continue creating array? y
mdadm: SET_ARRAY_INFO failed for /dev/md0: File exists

Anyone know why am I getting this error?  This is the first time (for this
install) that I'm trying to build a raid.  Where does this file exist?  On
my system disk or on the second disk I'm trying to build the raid on?

Thanks
Jay

Re: mdadm: SET_ARRAY_INFO failed for /dev/md0: File exists

[Neil Brown]

On Sunday May 2, me@heyjay.com wrote:
> Hi,
> 
> I did a fresh install of Sarge, updated the kernel to 2.4.26.  then did:
> 
> platinum:~#  mdadm -C /dev/md0 --level raid1 --raid-disks 2 missing
> /dev/hdc1
> mdadm: /dev/hdc1 appears to contain an ext2fs file system
>     size=117218240K  mtime=Wed Dec 31 18:00:00 1969
> Continue creating array? y
> mdadm: SET_ARRAY_INFO failed for /dev/md0: File exists
> 
> Anyone know why am I getting this error?  This is the first time (for this
> install) that I'm trying to build a raid.  Where does this file exist?  On
> my system disk or on the second disk I'm trying to build the raid
> on?

What does
  cat /proc/mdstat
show?  I suspect /dev/md0 has already been assembled somehow.

NeilBrown

> 
> Thanks
> Jay
> 
> -
> To unsubscribe from this list: send the line "unsubscribe linux-raid" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: mdadm: SET_ARRAY_INFO failed for /dev/md0: File exists

[me]

> What does
>   cat /proc/mdstat
> show?  I suspect /dev/md0 has already been assembled somehow.

platinum:~# cat /proc/mdstat
Personalities : [linear] [raid0] [raid1] [raid5]
md3 : active raid1 hdc1[1]
      20000768 blocks [2/1] [_U]

md1 : active raid1 hdc2[1]
      40001728 blocks [2/1] [_U]

md2 : active raid1 hdc3[1]
      40001728 blocks [2/1] [_U]

unused devices: <none>

But how??? I didn't build it.  Is it possible to remain after installs?  Can
I delete an md?  If so how?

Re: mdadm: SET_ARRAY_INFO failed for /dev/md0: File exists

[me]

Nevermind,  For the next newbie:

mdadm --stop /dev/md0
mdadm --zero-superblock /dev/hda1
mdadm --zero-superblock /dev/hdb1
...

Jay

----- Original Message ----- 
From: <me@heyjay.com>
To: "Neil Brown" <neilb@cse.unsw.edu.au>; <linux-raid@vger.kernel.org>
Sent: Monday, May 03, 2004 9:22 PM
Subject: Re: mdadm: SET_ARRAY_INFO failed for /dev/md0: File exists


> > What does
> >   cat /proc/mdstat
> > show?  I suspect /dev/md0 has already been assembled somehow.
>
> platinum:~# cat /proc/mdstat
> Personalities : [linear] [raid0] [raid1] [raid5]
> md3 : active raid1 hdc1[1]
>       20000768 blocks [2/1] [_U]
>
> md1 : active raid1 hdc2[1]
>       40001728 blocks [2/1] [_U]
>
> md2 : active raid1 hdc3[1]
>       40001728 blocks [2/1] [_U]
>
> unused devices: <none>
>
> But how??? I didn't build it.  Is it possible to remain after installs?
Can
> I delete an md?  If so how?
>
> -
> To unsubscribe from this list: send the line "unsubscribe linux-raid" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>
>

Re: mdadm: SET_ARRAY_INFO failed for /dev/md0: File exists

[Neil Brown]

On Monday May 3, me@heyjay.com wrote:
> > What does
> >   cat /proc/mdstat
> > show?  I suspect /dev/md0 has already been assembled somehow.
> 
> platinum:~# cat /proc/mdstat
> Personalities : [linear] [raid0] [raid1] [raid5]
> md3 : active raid1 hdc1[1]
>       20000768 blocks [2/1] [_U]
> 
> md1 : active raid1 hdc2[1]
>       40001728 blocks [2/1] [_U]
> 
> md2 : active raid1 hdc3[1]
>       40001728 blocks [2/1] [_U]
> 
> unused devices: <none>
> 
> But how??? I didn't build it.  Is it possible to remain after
> installs?  

If the partitions are marked as "Linux RAID Autodetect", or if some
startup script used mdadm or raidstart to start the arrays, then they
will reappear after reboot.

NeilBrown