First, plug your external drive to linux and follow this step.
Update your packages database
$ opkg update
Downloading http://192.168.77.246:8080/Packages.gz.
Inflating http://192.168.77.246:8080/Packages.gz.
Updated list of available packages in /var/opkg-lists/attitude_adjustment.
Install following package
$ opkg install kmod-usb-core # Kernel support for USB
$ opkg install kmod-usb2 # Kernel support for USB2 (EHCI) controllers
$ opkg install kmod-usb-ohci #Kernel support for USB OHCI controllers
$ opkg install kmod-usb-storage #Kernel support for USB Mass Storage devices
$ opkg install block-mount
$ opkg install kmod-fs-ext4 # Kernel module for the filesystem with which you formatted the partition you want to mount
$ opkg install fdisk # utility to create partitions table
To install package, you can always you this syntax
$ opkg install package_name
Before you step forward, you must prepare your disk partition, i choose fdisk for creating partition table, and i make 3 partition table, two partitions for my data and one for swap file. you can see here for instruction using fdisk.
Now, it is time to create filesystem on it, i choose ext3.
$ mkfs.ext3 /dev/sda1 for my data
$ mkfs.ext3 /dev/sda2 for my openwrt rootfs
$ mkswap /dev/sda3 for swap
Next step is create mount point and edit /etc/config/fstab, so every time you restart router, everything back as before :D
$ mkdir -p /home --> mount point /dev/sda1
$ mkdir -p /mnt/rootfs --> mount point /dev/sda2
Editing /etc/config/fstab, my fstab file looks like this
$ vi /etc/config/fstab
config global 'automount'
option from_fstab '1'
option anon_mount '1'
config global 'autoswap'
option from_fstab '1'
option anon_swap '0'
config mount
option target '/home'
option device '/dev/sda1'
option fstype 'ext3'
option options 'rw,sync'
option enabled '1'
option enabled_fsck '0'
config mount
option target '/mnt/rootfs'
option device '/dev/sda2'
option fstype 'ext3'
option options 'rw,sync'
option enabled '1'
option enabled_fsck '0'
config swap
option device '/dev/sda3'
option enabled '1'
Reboot it, after reboot check your mount point
$ df -h
Filesystem Size Used Available Use% Mounted on
rootfs 1.1M 652.0K 436.0K 60% /
/dev/root 2.0M 2.0M 0 100% /rom
tmpfs 14.3M 148.0K 14.1M 1% /tmp
tmpfs 512.0K 0 512.0K 0% /dev
/dev/mtdblock3 1.1M 652.0K 436.0K 60% /overlay
overlayfs:/overlay 1.1M 652.0K 436.0K 60% /
/dev/sda1 916.5G 477.8G 392.2G 55% /home
/dev/sda2 97.3M 4.1M 88.1M 4% /mnt/rootfs
Check swap
$free
total used free shared buffers
Mem: 29220 24864 4356 0 1660
-/+ buffers: 23204 6016
Swap: 98936 456 98480
Exrootfs - Whole external root (pivot root)
Do this on openwrt console
$ tar -C /overlay -cvf - . | tar -C /mnt/rootfs -xf -
$ mkdir -p /tmp/cproot
$ mount --bind / /tmp/cproot
$ tar -C /tmp/cproot -cvf - . | tar -C /mnt/rootfs -xf -
$ umount /tmp/cproot
Reboot
After Reboot, check your system mount point and swap memory
Before
$ df -h
Filesystem Size Used Available Use% Mounted on
rootfs 1.1M 652.0K 436.0K 60% /
/dev/root 2.0M 2.0M 0 100% /rom
tmpfs 14.3M 148.0K 14.1M 1% /tmp
tmpfs 512.0K 0 512.0K 0% /dev
/dev/mtdblock3 1.1M 652.0K 436.0K 60% /overlay
overlayfs:/overlay 1.1M 652.0K 436.0K 60% /
/dev/sda1 916.5G 477.8G 392.2G 55% /home
/dev/sda2 97.3M 4.1M 88.1M 4% /mnt/rootfs
After
$ df -h
Filesystem Size Used Available Use% Mounted on
rootfs 370.4M 15.4M 335.8M 4% /
/dev/root 2.0M 2.0M 0 100% /rom
tmpfs 14.3M 88.0K 14.2M 1% /tmp
tmpfs 512.0K 0 512.0K 0% /dev
/dev/sda2 370.4M 15.4M 335.8M 4% /overlay
overlayfs:/overlay 370.4M 15.4M 335.8M 4% /
/dev/sda1 916.5G 477.8G 392.2G 55% /home
Now you have a lot of space to install any applications :D
Enjoy it !!
