I recently updated a Ubuntu Dapper Drake (6.06) system to Edgy Eft
(6.10). Other than I had to reinstall/reconfigure my xserver everything
went ok. However, by the next reboot I noticed a strange
root=[long alphanumeric value] kernel parameter in my grub prompt.
After some investigation I found out that my
/etc/fstab contained the
same strange ids.
# /etc/fstab: static file system information. # # <file system> <mount point> <type> <options> <dump> <pass> proc /proc proc defaults 0 0 # /dev/hdc5 -- converted during upgrade to edgy UUID=048b4608-5241-4dc4-8671-f8290cb55af5 / ext3 defaults,errors=remount-ro 0 1 # /dev/hdc1 -- converted during upgrade to edgy UUID=05c63290-f5b8-4afb-97c1-fb7e15ad6ed8 /boot ext2 defaults 0 2 # /dev/hdc10 -- converted during upgrade to edgy UUID=06ee7e3e-768b-4a51-a31f-0e70ec314e81 /data ext3 defaults 0 2 # /dev/hdc7 -- converted during upgrade to edgy UUID=56ef33df-9f30-4577-b1de-83b540fd3519 /home ext3 defaults 0 2 # /dev/hdc11 -- converted during upgrade to edgy UUID=9628b57a-cd57-4ffb-a0e7-6d2bc349e46b /media/hdc11 ext3 defaults 0 2 # /dev/hdc12 -- converted during upgrade to edgy UUID=caa74b76-416b-46aa-8c0a-f6348f6afbcd /media/hdc12 ext3 defaults 0 2 # /dev/hdc13 -- converted during upgrade to edgy UUID=fe873ec7-3176-4aad-b0b1-9164f938f213 /media/hdc13 ext3 defaults 0 2 # /dev/hdd1 -- converted during upgrade to edgy UUID=9E745EF6745ED11F /media/hdd1 ntfs defaults,nls=utf8,umask=007,gid=46 0 1 # /dev/hdd5 -- converted during upgrade to edgy UUID=78DB-0025 /media/hdd5 vfat defaults,utf8,umask=007,gid=46 0 1 # /dev/hdc9 -- converted during upgrade to edgy UUID=b43c2193-3c00-48d0-8c29-c2fa7212c457 /usr ext3 defaults 0 2 # /dev/hdc8 -- converted during upgrade to edgy UUID=7cec1fb3-c2f2-46dc-9782-7228d57b9f2b /var ext3 defaults 0 2 # /dev/hdc6 -- converted during upgrade to edgy UUID=6996378e-a37b-49b8-8e91-65164bef7626 none swap sw 0 0 /dev/hda /media/cdrom0 udf,iso9660 user,noauto 0 0 /dev/fd0 /media/floppy0 auto rw,user,noauto 0 0
My first thought: what a mess! Luckily they left some comments in there.
So what is the purpose of those numbers which are not so human friendly?
They should uniquely identify a given partition. Which means you could
swap your disks, USB sticks, whatever and the system will still mount
the correct partition at the right place. Another thing this mechanism
tries to work around is, that the device names depend on module load
order. With the development in recent kernels which try to scan the
hardware and detect devices in parallel, to speed up boot time, it will
be entirely random which devices turns up as
You may ask how can I check the mappings between UUIDs and devices? Good
question – there are a few different ways,
/sbin/blkid will happily
print a list of device names, filesystem labels and UUIDs for you even
if you aren’t root. While
sudo vol_id -u <partion> will give you only
the exact UUID for the requested partition.
After I have informed myself about those UUIDs I am no longer that scared but I still think this is a sub optimal solution they are just way too human unfriendly. A solution based on disk LABELS is probably the better approach.