How to make a NAS with an OpenWrt router

Ingredients

• OpenWrt router with USB port (such as TP-Link WR1043ND) already flashed with OpenWrt and connected to the Internet

• external USB hard drive
• cables to connect and power the hardware

Steps

root@QQ:~# opkg update

root@QQ:~# opkg install kmod-fs-ext4

root@QQ:~# opkg install kmod-usb-storage

plug the disk into the router's USB port

root@QQ:~# dmesg
...
SCSI subsystem initialized
Initializing USB Mass Storage driver...
scsi0 : SCSI emulation for USB Mass Storage devices
usbcore: registered new interface driver usb-storage
USB Mass Storage support registered.
usb-storage: device found at 2
usb-storage: waiting for device to settle before scanning
scsi 0:0:0:0: Direct-Access     WD       Ext HDD 1021     2021 PQ: 0 ANSI: 4
sd 0:0:0:0: [sda] 1953519616 512-byte logical blocks: (1.00 TB/931 GiB)
usb-storage: device scan complete
sd 0:0:0:0: [sda] Write Protect is off
sd 0:0:0:0: [sda] Mode Sense: 17 00 10 08
sd 0:0:0:0: [sda] Assuming drive cache: write through
sd 0:0:0:0: [sda] Assuming drive cache: write through
 sda: sda1
sd 0:0:0:0: [sda] Assuming drive cache: write through
sd 0:0:0:0: [sda] Attached SCSI disk