hard-linking /data folders to /home with fstab

[akand074]

So initially I had / on my SSD and /home on my HDD. I just did a clean install of Oneiric but put my entire filesystem including /home on my SSD and instead had my old /home folder mounted at /media/data. I'm now trying to hard-link the two so that whenever I refer to any of my folders in /home it automatically looks in my /media/data folders seamlessly as if they were the same folder. What I did was put the folders into the correct place and then changed the entire /media/data folder owner to my user. Then I added this to the end of /etc/fstab via gksu gedit /etc/fstab:

LABEL=Data  /media/data  ext4  defaults  0  0
/media/data/Documents  /home/andrew/Documents  none  bind  0  0
/media/data/Downloads  /home/andrew/Downloads  none  bind  0  0
/media/data/Music  /home/andrew/Music  none  bind  0  0
/media/data/Pictures  /home/andrew/Pictures  none  bind  0  0
/media/data/Videos  /home/andrew/Videos  none  bind  0  0
/media/data/Public  /home/andrew/Public  none  bind  0  0

After I restart it fails to mount the partition so I press "S" to skip and when I log in and try to mount it manually it basically says I can't because it belongs to root. I then remove what I had added to the end of fstab and restart and it boots again and mounts fine (though not hardlinked). Anyone have any clue what may be the problem?

[akand074]

From a bit of reading, apparently you can't create hard-links between different file systems (and often not even with directories). Though, what I'm trying to do isn't actually a hard-link. I'm actually trying to mount each folder in a different location. Which should be possible even from different hard drives, but I'm not sure. Anyways, in the mean time I've created symbolic links to all the folders.

[nothingspecial]

Basic checks first.

1. The drive is labled Data and is formatted ext4

2. The directory /media/data exists. The automount feature will create the directory /media/DATA when you plug it in. If you mount it with fstab the directory has to exist already.

3. You own the drive.

4. The directories in your /home/$USER exist and are empty.

I have no idea if ssds effect any of this because I have never used one.

[akand074]

Basic checks first.

1. The drive is labled Data and is formatted ext4

I just copied what you had in your fstab and changes the folders to mine. I didn't distinctly label a drive Data or made any changes.

2. The directory /media/data exists. The automount feature will create the directory /media/DATA when you plug it in. If you mount it with fstab the directory has to exist already.

The folder already exists with all the sub folders I wanted mounted within /home

3. You own the drive.

I right clicked /media and changed it's owner to my user along with all enclosed files and folders. If I right click /media/data it says my user owns it. Is that what you mean?

4. The directories in your /home/$USER exist and are empty.

I have no idea if ssds effect any of this because I have never used one.

They do exist and are empty, though currently they are actually just folders with a symbolic link to the folders in /media/data but that can easily be reverted.

[oldfred]

I just use soft links and only mount the data partition in /mnt/data.

But bind is supposedly a better way. Your SSD may mount too fast for HDD to mount with the bind. Then you may want an upstart script.

Another way to share:
HowTo: Create shared directory for local users (with bindfs).
http://ubuntuforums.org/showthread.php?t=1460472
With upstart script
http://ubuntuforums.org/showthread.php?t=1771773&page=5
kansasnoob's sharing and Morbius1 use of bindfs
http://ubuntuforums.org/showthread.php?t=1495798

[Morbius1]

@oldfred, thanks for the plug but I think bindfs is going to have the same problem as a normal bind in fstab. I thinks it's a timing issue. I would go with the upstart idea:

[1] Create an upstart script named "home-mounts.conf"

  gksu gedit /etc/init/home-mounts.conf

[2] The content of that file would look something like this:

# Remount partitions with bind
#
description "Bind Data Subdirectories to Andres' Home Directory"

start on stopped mountall

script
mount --bind /media/data/Documents  /home/andrew/Documents
mount --bind /media/data/Downloads  /home/andrew/Downloads
mount --bind /media/data/Music  /home/andrew/Music
mount --bind /media/data/Pictures  /home/andrew/Pictures
mount --bind /media/data/Videos  /home/andrew/Videos
mount --bind /media/data/Public  /home/andrew/Public
end script

It's the "start on stopped mountall" that does the trick since it won't run the script until everything in fstab ( i.e., /media/data ) is mounted first.

[nothingspecial]

I didn't distinctly label a drive Data or made any changes.

While I bow to the vastly superior knowledge of oldfred and Morbius1.....

if your drive is not labeled Data the whole thing will fail.

[akand074]

While I bow to the vastly superior knowledge of oldfred and Morbius1.....

if your drive is not labeled Data the whole thing will fail.

I see. I'm going to give Morbius1's route a go a little later perhaps. Thanks for the help!

Yeah when I first got my SSD I had a lot of problems where the OS was loading faster than the config files in /home and would thus load with an odd look. It also used to hang a bit on boot. With oneiric now having /home on the SSD I've had no problems and my boot time dropped significantly. Under 15 seconds now it seems.

Anyways, I'll give that script a go. Worst case, the soft links do the job fine, I would though preferably like to not have the HDD show up in devices and be able unmount it (might eject it by accident) but it's not the end of the world.

[dcstar]

I just use soft links and only mount the data partition in /mnt/data.

But bind is supposedly a better way.
.......

A matter of opinion, apparently:

http://www.fedoraforum.org/forum/sho...d.php?t=150277

And this is worth a peruse:

http://aplawrence.com/Linux/mount_bind.html

[Morbius1]

While I bow to the vastly superior knowledge of oldfred and Morbius1.....

if your drive is not labeled Data the whole thing will fail.

I missed that in this thread. So much for "vastly superior knowledge"

You can get around this problem by not using LABEL in fstab but do it by UUID. So instead of this:

LABEL=Data /media/data ext4 defaults 0 0

It becomes this:

UUID=e92eaf02-ff61-4db0-9397-35f1aadb98e8 /media/data ext4 defaults 0 0

TO find the correct UUID for you partition run the following command:

sudo blkid -c /dev/null