On Monday July 1, thicks@speedfreak.org wrote:
> This is the first time I am setting up raid using the mdadm tool. This
> is what I am trying to do.
>
> The sever is as follows: 2 drives at 10gig
> 2 drives at 80gig
> hda2 is /
> hdd1 is my /home
>
> I have the other drives in ad ready and would like to set up the 2 10
> gig's as a mirror and the 2 80 gig as raid0
>
> At the shell I run this command
>
> mdadm --create /dev/md0 --level=1 --raid-disks=2 /dev/hda2 /dev/hdb1
> and get the following output:
>
> mdadm: /dev/hda2 appears to contain an ext2fs file system
> size=7269412K mtime=Mon Jul 1 11:56:16 2002
> mdadm: /dev/hdb1 appears to contain an ext2fs file system
> size=7333640K mtime=Mon Jul 1 11:56:29 2002
> Continue creating array? y
> mdadm: SET_ARRAY_INFO failed for /dev/md0: File exists
>
> Could someone please help me with this problem. I am having a really
> hard time finding any info on the web about this.
hda2 is mounted as / and you are trying to make a raid1 array
containing it. This cannot work.
What you want to do is:
mdadm --create /dev/md0 --level=1 --raid-disks=2 missing /dev/hdb1
to create a degraded array containing just hdb1.
Then:
mkfs /dev/md0
mount /dev/md0 /mnt
cp -ax / /mnt
to copy your root filesystem onto /dev/md0.
Then tell lilo:
append= "root=/dev/md0 md=0,/dev/hdb1"
and tell fstab that root in on /md0, and reboot.
Then you should be be running with root on /dev/md0 which consists of
/dev/hdb1, and /dev/hda2 will be unused.
Then
mdadm --add /dev/md0 /dev/hda2
to add hda2 to the mirror. Wait for resync.
Change lilo.conf to say the right thinggs, run lilo and reboot.
Note: it appears that hdb1 is bigger than hda2. If this is so you
will need to give a --size= to mdadm when created md0 so that it is
small enough to be able to use hda2.
Subtract 128 K from the size of hda2, so
mdadm --create /dev/md0 --size=7269280 ......
NeilBrown
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