Problem with duplicate UUID's on partitions

[deejay_99]

I just installed Ubuntu 9.04 and have the following partitions:




dev/sda1 ... mounted as "windows_old" .... fat 32 on separate old 27 gig hard drive .... UUID=1174-1cd3
dev/sdb1 ... ... mounted as "windows" .... fat 32 - 117gig partition for windows xp on new hard drive ... UUID=1174-1cd3
dev/sdb2 ..... ubuntu "/" ..... 47 gig partition on new hard drive
dev/sdb5 .... ubuntu "/home" .... 66 gig partition on new hard drive
dev/sdb3 ... swap ... 2 gig partition on new hard drive



Both "windows_old" and "windows" are mounting the dev/sdb1 ... when "windows_old" should be mounting the /dev/sda1 partition.


Here is my fstab:


# /etc/fstab: static file system information.

# / was on /dev/sdb2 during installation
UUID=1665d875-436c-4cf3-a777-b6f03504d6e5 / ext3 relatime,errors=remount-ro 0 1


# /home was on /dev/sdb5 during installation
UUID=8e41ee9e-15e0-4d8d-a3d2-9fc9d1a5dd32 /home ext3 relatime 0 2


# /windows was on /dev/sdb1 during installation
UUID=1174-1CD3 /windows vfat utf8,umask=007,gid=46 0 1


# /windows_orig was on /dev/sda1 during installation
UUID=1174-1CD3 /windows_orig vfat utf8,umask=007,gid=46 0 1


/dev/sdb3 none swap sw 0 0


/dev/scd0 /media/cdrom0 udf,iso9660 user,noauto,exec,utf8 0 0


Here is my mtab:


/dev/sdb2 / ext3 rw,relatime,errors=remount-ro 0 0
tmpfs /lib/init/rw tmpfs rw,nosuid,mode=0755 0 0
proc /proc proc rw,noexec,nosuid,nodev 0 0
sysfs /sys sysfs rw,noexec,nosuid,nodev 0 0
varrun /var/run tmpfs rw,nosuid,mode=0755 0 0
varlock /var/lock tmpfs rw,noexec,nosuid,nodev,mode=1777 0 0
udev /dev tmpfs rw,mode=0755 0 0
tmpfs /dev/shm tmpfs rw,nosuid,nodev 0 0
devpts /dev/pts devpts rw,noexec,nosuid,gid=5,mode=620 0 0
fusectl /sys/fs/fuse/connections fusectl rw 0 0
lrm /lib/modules/2.6.28-13-generic/volatile tmpfs rw,mode=755 0 0
/dev/sdb5 /home ext3 rw,relatime 0 0
securityfs /sys/kernel/security securityfs rw 0 0
binfmt_misc /proc/sys/fs/binfmt_misc binfmt_misc rw,noexec,nosuid,nodev 0 0
gvfs-fuse-daemon /home/doug/.gvfs fuse.gvfs-fuse-daemon rw,nosuid,nodev,user=doug 0 0
/dev/sdc1 /media/USB\040Mobile\040Drive fuseblk rw,nosuid,nodev,allow_other,blksize=4096 0 0
/dev/sdb1 /windows_orig vfat rw,utf8,umask=007,gid=46 0 0
/dev/sdb1 /windows vfat rw 0 0


The bottom two lines show both "windows" and "windows_old" mounts pointing to /dev/sdb1 ... I assume because they have been both assigned the same UUID.


Any ideas on how I can fix this?


(Also, in mtab, why does the first line /dev/sdb2 / ext3 rw,relatime,errors=remount-ro 0 0 show an error?Does this need fixing?)

[eternalsword]

(Also, in mtab, why does the first line /dev/sdb2 / ext3 rw,relatime,errors=remount-ro 0 0 show an error?Does this need fixing?)


all that means is if there are errors with mounting the disk normally, it will try remounting it read-only so you can possibly recover data from a failing partition. Nothing to fix there.

The primary issue is that windows_orig and windows have been assigned to mount the same partition, hence identical UUIDs. To fix this, you'll need to find out the UUID for /dev/sda1

you can find out the UUID for /dev/sda1 by entering the following command in a terminal


ls -l /dev/disk/by-uuid | grep 'sda1'

this should produce something like

lrwxrwxrwx 1 root root 10 2009-07-05 23:04 edc5f364-2a69-4204-a328-11c059e00f71 -> ../../sda1

the section containing the uuid is in bold, go ahead and copy that part from your output to your clipboard.

if the UUID matches 1174-1CD3, rerun the previous command except replace sda1 with sdb1.

now make a backup of your fstab (always good practice to back-up system files before modification).


sudo cp /etc/fstab /etc/fstab.bak

now edit the fstab


gksu gedit /etc/fstab

paste in the UUID that you copied earlier in the line corresponding to windows_orig if sda1 gave you a different UUID or to windows if sdb1 gave you a different UUID.

[deejay_99]

Thanks for your suggestion. The uuid's show the same for both:

root@ubuntu1:~# blkid
/dev/sda1: UUID="1174-1CD3" TYPE="vfat" LABEL="WINDOWS_ORI"
/dev/sdb1: UUID="1174-1CD3" TYPE="vfat" LABEL="WINDOWS"
/dev/sdb2: UUID="1665d875-436c-4cf3-a777-b6f03504d6e5" TYPE="ext3"
/dev/sdb3: TYPE="swap"
/dev/sdb5: UUID="8e41ee9e-15e0-4d8d-a3d2-9fc9d1a5dd32" TYPE="ext3"
/dev/sdc1: UUID="74D4F67CD4F63FC2" LABEL="USB Mobile Drive" TYPE="ntfs"

Why would Ubuntu issue the same UUID to two different partitions (on separate hard drives!)?

I should mention that the "windows" and "windows_orig" files/directories were an exact copy of the other ... could this have confused ubuntu, thinking they were the same info, so it gave them the same UUID?

Is there any way to change or create a new UUID? If I unmount, modify the partition, and remount would a new UUID be assigned? Any other way?

[dandnsmith]

There is some info (I suggest google for it) about UUIDs and Windows.

An important thing to remember is that Ubuntu doesn't issue the UUIDs for the Windows partitions, they are information which has been put there by the Windows installation.

If you try changing UUID with linux tools, you may find you've clobbered the Windows installation (and it will treat it as a corrupt filesystem) - so do some research first.

[eternalsword]

Since they are reporting the same UUID, you can use the actual devices instead.

So this

# /windows was on /dev/sdb1 during installation
UUID=1174-1CD3 /windows vfat utf8,umask=007,gid=46 0 1


# /windows_orig was on /dev/sda1 during installation
UUID=1174-1CD3 /windows_orig vfat utf8,umask=007,gid=46 0 1

would become

# /windows was on /dev/sdb1 during installation
/dev/sdb1 /windows vfat utf8,umask=007,gid=46 0 1


# /windows_orig was on /dev/sda1 during installation
/dev/sda1 /windows_orig vfat utf8,umask=007,gid=46 0 1

UUID in fstab is really only needed for mounting devices that shift around in order. In your case I think you would be safe.

[deejay_99]

Thanks for all your help. I didn't realize UUID was assigned by Windows!

I did some more digging, and found out you can mount partitions by label. I unmounted the two partitions, labelled them and remounted using the label as the reference, not the UUID ... it worked!!!

All your comments helped this newbie learn more about Ubuntu, mounitng partitions and the file system.