Undo a RAID mirror

curlyroger · 07-14-2005, 01:47 PM

I have a FC1 system with a RAID mirror that I want to undo. Basically, I want to remove the secondary disk and use the primary as a normal drive.

The way I think it should be done is:

1 - Remove secondary drive
2 - Boot off CD
3 - Edit /etc/fstab and change mdX to hdaX
4 - Run fdisk on /dev/hda and change the partition types from 'Linux raid autodetect' to Linux (and Linux swap)
5 - Boot up

Is this possible/correct? What about the MBR? Here's the config:

Code:

[root@host root]# cat /etc/raidtab
raiddev             /dev/md2
raid-level                  1
nr-raid-disks               2
chunk-size                  64
persistent-superblock       1
nr-spare-disks              0
    device          /dev/hda3
    raid-disk     0
    device          /dev/hdc3
    raid-disk     1
raiddev             /dev/md0
raid-level                  1
nr-raid-disks               2
chunk-size                  64
persistent-superblock       1
nr-spare-disks              0
    device          /dev/hda1
    raid-disk     0
    device          /dev/hdc1
    raid-disk     1
raiddev             /dev/md1
raid-level                  1
nr-raid-disks               2
chunk-size                  64
persistent-superblock       1
nr-spare-disks              0
    device          /dev/hda2
    raid-disk     0
    device          /dev/hdc2
    raid-disk     1

[root@host root]# cat /etc/fstab
/dev/md2        /       ext3    usrquota,grpquota,defaults      1       1
/dev/md0                /boot                   ext3    defaults        1 2
none                    /dev/pts                devpts  gid=5,mode=620  0 0
none                    /proc                   proc    defaults        0 0
none                    /dev/shm                tmpfs   defaults        0 0
/dev/md1                swap                    swap    defaults        0 0

[root@host root]# fdisk -l

Disk /dev/hdc: 80.0 GB, 80026361856 bytes
255 heads, 63 sectors/track, 9729 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot    Start       End    Blocks   Id  System
/dev/hdc1   *         1        13    104391   fd  Linux raid autodetect
/dev/hdc2            14       241   1831410   fd  Linux raid autodetect
/dev/hdc3           242      9729  76212360   fd  Linux raid autodetect

Disk /dev/hda: 80.0 GB, 80026361856 bytes
255 heads, 63 sectors/track, 9729 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot    Start       End    Blocks   Id  System
/dev/hda1   *         1        13    104391   fd  Linux raid autodetect
/dev/hda2            14       241   1831410   fd  Linux raid autodetect
/dev/hda3           242      9729  76212360   fd  Linux raid autodetect

Thanks!

Matir · 07-14-2005, 03:12 PM

What you say makes sense, but there's no guarantee that it would get f'ed up in the process.

I would make sure things are thoroughly backed up before attempting this.

As a general FYI: why did you raid mirror swap? Just for the stability in case of a disk failure?

lacerto · 09-18-2005, 01:54 PM

I've did exactly the same thing - two 250gb sata drives mirrored.

I initially did it just to see it it worked..and it did. I then customised my system, and would rather not have to re-install. I now want the extra drives space back though.

How did you get on with this?

L

EDIT: I sould add that I'm using Linux raid, not hardware or BIOS raid.