Question:

My Debian (up to date) system will automount USB pen drives on the fly, but not a 1 Tb external USB drive (Iomega), which will mount but it has to be attached before booting. How to I change the behaviour for the Iomega usb large drive so I can mount it after the system is up? Thanks.

Answer:

If your 1 Tb external USB drive mounts when it is attached before booting you may have a line in your /etc/fstab configuration file which mounts it during the boot time. If this is the case and you plug in your external USB drive after the boot, execute as a root user:

# mount -a

This will mount all devices which are not currently mounted, including your Iomega USB drive.

However, this may not be the most reliable solution since the base device file name for your drive can be different every time you plugin your USB disk. Since you have already mentioned that you are using other USB pen drives, your base device file name for your Iomega USB disk can be anything like: /dev/sdb1, /dev/sdd1 or /dev/sdXn .

I have exactly the same problem with my external WD USB drive as it mounts automatically in Fedora but not in Debian. Therefore, I recommend use autofs. autofs is very simple a neat solution. It takes little bit of configuration but its worth it !

Make USB device base name permanent

To avoid any confusion whether base name for your USB block device is /dev/sdb1, /dev/sdd1 or /dev/sdXn we make it permanently /dev/Iomega anytime you plug it in. This can be done with help of udev device manager. You should have udev already installed on your system, otherwise install it with:

# apt-get install udev

Next, search for a current base name of your external USB disk using fdisk command:

# fdisk -l

This will return something like this:

OUTPUT:

Disk /dev/sdc: 2000.3 GB, 2000396746752 bytes
255 heads, 63 sectors/track, 243201 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x001425a0

   Device Boot      Start         End      Blocks   Id  System
/dev/sdc1               1      243201  1953512001    b  W95 FAT32

Where the base name for your external USB device is /dev/sdc. Next, use udevinfo command with /dev/sdc as an argument to get model attribute:

$ udevinfo -a -p /sys/block/sdc/ | grep model
    ATTRS{model}=="Ext HDD 1021    "

Now, that we have model attribute, we can add it to /etc/udev/rules.d/custom.rules by following line:

SUBSYSTEM=="scsi", ATTRS{model}=="Ext HDD 1021    ", SYMLINK+="Iomega%n"

At this point all we need to do is restart udev device manager:

# /etc/init.d/udev restart
Stopping the hotplug events dispatcher: udevd.
Starting the hotplug events dispatcher: udevd. 

Plug in external USB and your new base name is:

ls -l /dev/Iomega*
lrwxrwxrwx 1 root root  3 2011-02-23 12:36 /dev/Iomega -> sdc
lrwxrwxrwx 1 root root 12 2011-02-23 12:36 /dev/Iomega0 -> bsg/14:0:0:0
lrwxrwxrwx 1 root root  4 2011-02-23 12:36 /dev/Iomega1 -> sdc1
lrwxrwxrwx 1 root root  3 2011-02-23 12:36 /dev/Iomega3 -> sg3

Please note that /dev/Iomega1 points to a /dev/sdc1, which is exactly the partition we are interested in and we use it next to configure autofs.

Setting up autofs

First we need to install autofs:

# apt-get install autofs

Configuring autofs is rather simple task. All we need to do is to edit two simple files.

Let's start with master file by appending a following line:

/media/   /etc/auto.ext-usb --timeout=10,defaults,user,exec,uid=1000

Next, edit /etc/auto.ext-usb file which we included in a master configuration file configuration:

Iomega            -fstype=auto           :/dev/Iomega1

Restart autofs:

# /etc/init.d/autofs restart

Testing autofs configuration

We are done! Every time you now plug in your external Iomega USB drive aufosf will add your device to a list of Active Mount Points. Plugin your external USB drive now and execute:

/etc/init.d/autofs status

OUTPUT:

Configured Mount Points:
------------------------
/usr/sbin/automount --timeout=10 /media file /etc/auto.ext-usb ,defaults,user,exec,uid=1000

Active Mount Points:
--------------------
/usr/sbin/automount --pid-file=/var/run/autofs/_media.pid --timeout=10\ 
 /media file /etc/auto.ext-usb ,defaults,user,exec,uid=1000

and

# mount

OUTPUT:

automount(pid7124) on /media type autofs (rw,fd=4,pgrp=7124,minproto=2,maxproto=4)

Please note, although our drive is now listed as an active mount point the disk is not mounted yet! autofs only waits for user to access specified mount point directory and once that happens it will mount the filesystem.

Example:

$ cd /media/
$ ls
$ cd Iomega
$ ls
lost.dir  music  picture  ps3  video mystuff
$ cd ..
$ ls
Iomega

From the output above you can see that Iomega directory was created only when I tried to access it. Every time you now plug in you USB external disk you can instantly access it via some sort of Desktop or Bookmark shortcut. I hope this helps !