Once you have obtained Basic USB support, you may want to connect a USB storage device (USB stick, USB harddisk, etc) to your router. This HowTo will tell you the steps. You should be aware that any storage device has to be partitioned and formated with a File system (ie. ext3) before data can be addressed as files by the OS.

1. obtain Basic USB support on your OpenWrt-powered device
2. install storage and file system requirements (Required Packages), as shown below. Minimum you need kmod-usb-storage to see usb disk devices.
3. connect the already partitioned and formatted storage device (e.g. hard disc) to your OpenWrt-powered device; the device itself and its partitions should immediately be available as Device files under /dev/, for example dev/sda, /dev/sda1, /dev/sda2, etc.

If you are planning on sharing your USB storage with Samba, and/or using it to share large multimedia content over UPnP, e.g. with ushare, you should use ext3 or ext4 rather than ext2. Default Ext2 partitions will be limited to files of no more than 4 Gb, but this restriction is eliminated with the newer filesystems. To retain good performance with the newer filesystems, particularly on flash USB storage, you should also consider disabling journaling with the "-O ^has_journal" when using mkfs.ext4 to format the filesystem. Also for ext4, the "extent" formatting option (e.g. "-O ^has_journal,extent") will make filesystem access to large files more performant.

As of r26314 block-extroot and block-hotplug have been merged with block-mount. That means that once you select block-mount the scripts for extroot mounting and hotplug mounting are installed. block-mount can be installed even if you have not selected a block device package, but if you want to actually mount a block device you must still install the drivers (block device package) as well as the filesystem you want to use (e.g. ext4, kmod-fs-ext4 and e2fsprogs). ( This may not be true for Backfire (10.03.1, r29592) users. It was confirmed that block-mount is not enough to make fstab work → block-hotplug had to be installed separately with opkg install block-hotplug. Its possible that same might be said about the block-extroot package.)

• kmod-usb-storage required Kernel support for USB Mass Storage devices
• kmod-usb-storage-extras optional Kernel support for some more drivers, such as for SmartMedia card readers
• block-mount optional & recommended Scripts used to mount and check block devices (filesystems and swap). Required for fstab configuration.
  • Since Attitude Adjustment it includes:
    • block-hotplug required for configuration with /etc/config/fstab
    • block-extroot required for rootfs on external storage
  • Dependencies:
    • blkid Command-line utility to locate/print block device attributes
    • swap-utils This package contains a collection of tools for managing swap space: mkswap, swapon and swapoff

• kmod-fs-???? required the filesystem you formated your partition in

• kmod-usb2 optional USB2.0 support, needed for stable USB1.0 usage with some devices (e.g. La Fonera 2), too.

• kmod-usb-ohci or kmod-usb-uhci optional USB1.0 support

• kmod-scsi-generic probably required Any mass storage is a generic SCSI device.

As of r26645 the modules for ext2 and ext3 (kmod-fs-ext2 and kmod-fs-ext3) are no longer available. You can use the module for ext4 kmod-fs-ext4 to mount ext2/ext3 as well, but then you have to mount your ext2 or ext3 partition like ext4 partition: mount -t ext4 /dev/sda1 /mnt/share -o rw,sync

OpenWrt-Forum: Benchmarks with different filesystems

Available file systems and their packages can be listed with opkg update; opkg list "kmod-fs*".

You are not required to use NTFS or FAT in order to access the disk from Microsoft Windows! See http://wiki.ubuntuusers.de/Linux-Partitionen_unter_Windows on HowTo access Linux filesystems from Windows. Thus native Linux file systems like ext2 or ext3 are the first choice when working with Linux. Don't bother with NTFS, VFAT and the like. They all have some quirks we could do without.

If, for whatever reasons, you insist to utilize NTFS as file system, you may find Writable NTFS helpful.

For some filesystems, like for VFAT, you need to additionally install language packages (codepages / charsets) to handle the filenames. If your mount fails, look in dmesg - a message like

FAT: codepage cp437 not found

means that you need NLS codepage 437, and a message like

FAT: IO charset iso8859-1 not found

means that you need NLS ISO 8859-1.

***''kmod-nls-base''** Kernel module for NLS (Native Language Support)

Available NLS files and their packages can be listed with opkg update; opkg list "kmod-nls*".

→/etc/config/fstab

There is nothing to configure! Read the manpage for mount. Pay special attention to the options! You can only mount a partition to an existing directory. You can create it with mkdir, for example:

mkdir -p /mnt/shares

To manually mount a partition:

mount -t ext3 /dev/sda2 /mnt/shares -o rw,sync

To unmount:

umount /mnt/shares

To mount a swap partition:

swapon /dev/sda1

To unmount a swap partition:

swapoff /dev/sda1

opkg update
opkg install kmod-usb-storage block-mount block-hotplug kmod-fs-ext4
swapon /dev/sda1
mkdir -p /mnt/share
mount -t ext3 /dev/sda2 /mnt/share -o rw,sync

Other example is how to external usb stick with FAt32 partition (but we'll keep ext4 support also)

opkg update
opkg install kmod-usb-storage block-mount block-hotplug kmod-fs-ext4 kmod-fs-vfat kmod-nls-cp437 kmod-nls-iso8859-1
mkdir -p /mnt/usb
mount -t vfat /dev/sda1 /mnt/usb

As of r26314 block-extroot and block-hotplug have been merged with block-mount. That means that once you select block-mount the scripts for extroot mounting and hotplug mounting are installed. block-mount can be installed even if you have not selected a block device package, but if you want to actually mount a block device you must still install the drivers (block device package) as well as the filesystem you want to use (e.g. ext4, kmod-fs-ext4 and e2fsprogs)

Install the packages block-mount and block-hotplug, they will take care of this and also enable automatic mount when device is plugged in. The configuration file is /etc/config/fstab.

Example settings in fstab for mounting to /mnt/share with automatic detection of the file system:

And to make the fstab settings effective in current session run:

/etc/init.d/fstab start

To make the fstab settings effective after every reboot run:

/etc/init.d/fstab enable

UCI CLI commands:

/etc/init.d/fstab stop
uci add fstab mount
uci set fstab.@mount[-1].device=/dev/sda1
uci set fstab.@mount[-1].options=rw,sync
uci set fstab.@mount[-1].enabled_fsck=0
uci set fstab.@mount[-1].enabled=1
uci set fstab.@mount[-1].target=/mnt/share
uci commit fstab
/etc/init.d/fstab start

Delete with UCI CLI commands:

/etc/init.d/fstab stop
uci delete fstab.@mount[0]
uci commit fstab
/etc/init.d/fstab start

Note: In order to do fsck (aka CHKDSK) of FAT32/VFAT partitions before mounting (i.e. during the boot process), you should read the following tickets: Incorrect log output for mount point file systems without a fsck, and Missing fsck function for block-mount/-hotplug of dos/vfat filesystems

Actually there are packages in the OpenWrt repositories with which you can partition, format and check filesystems:

• fdisk (for help with partitioning see TLDP)
• e2fsprogs Contains the essential ext2 filesystem utilities e2fsck, mke2fs, debugfs, dumpe2fs and tune2fs, and also most of the other core ext2 filesystem utilities available. for help with formatting see TLDP

Note: In order to perform a e2fsck on 1 GiB partition, you will need at least 1 MiB of RAM.²⁾ The same is true for mke2fs. You can solve this by mounting a SWAP partition (or by using a device with enough RAM).

Once you successfully mounted your partition, you may want to install packages onto it. Please see Installation.Destination for that.

If you plan to install kernel modules on a USB drive you might want to read this: https://dev.openwrt.org/ticket/10739

You may create an empty file to indicate that the disk is not plugged in so that you don't put files directly onto NAND by doing

touch /mnt/usbstorage/USB_DISK_NOT_PRESENT
chmod 444 /mnt/usbstorage -R

mount the external drive:
(where sda1 is your drive, see fdisk -ls, and /mnt/hdd is the point where you wish to mount. Use md to make the directories)

ntfs-3g -o rw,noatime /dev/sda1 /mnt/hdd

Then make the following script:

nano /etc/init.d/hdd

And the contents:
(In this script, You can control other processes, like transmission, whitch uses Your external drive)

Enter the required permissions to it.

chmod a+x /etc/init.d/hdd

create a swapfile, then format and turned on.

dd if=/dev/zero of=/mnt/hdd/swapfile bs=1M count=64
mkswap /mnt/hdd/swapfile
swapon /mnt/hdd/swapfile

To see if work:

free

Now let's do a virtual disk. You need an additional package.

 
opkg update
opkg install kmod-fs-ext3 kmod-loop e2fsprogs
insmod ext3
insmod loop

Then, create, and format the disk:

dd if=/dev/zero of=/mnt/hdd/owrt_loop bs=1M count=128
mke2fs -j -F -b 1024 /mnt/hdd/owrt_loop

To be able to use, plug-in for OpenWrt:

mkdir /mnt/loopdisk
mount -o loop /mnt/hdd/owrt_loop /mnt/loopdisk

Now our system is not only the OpenWrt xMB, but x+128 MB

Write in /etc/opkg.conf file into the following line

→#installation.destinations

To install package:

opkg -dest usb install package

To delete package:

opkg -dest usb remove package

Prefer EXT2 or EXT3 file system.

Symptoms: I have installed kmod-usb-storage, but I don't see sda, sda1, sda2 or similar in /dev directory.

Solution: Make sure you have started and enabled usb startup script:

/etc/init.d/usb start
/etc/init.d/usb enable

Symptoms: You are trying to mount ext2 or ext3 partition and you have installed only kmod-fs-ext4. Neither mount command nor fstab works. The kmod-fs-ext4 issue definitely applies to Backfire, but is not an issue for Attitude Adjustment (tested on Attitude Adjustment RC1).

Solution a): you have to make sure that you are trying to mount the ext2 or ext3 partition like it was ext4 partition. Example /etc/config/fstab config and mount command follows:

mount -t ext4 /dev/sda1 /mnt -o rw,sync

Solution b): install kmod-fs-ext3 or kmod-fs-ext2 filesystem.

opkg update
opkg install kmod-fs-ext3

Note: If you are having trouble with fstab, see fstab troubleshooting.

Note: If you are having trouble using storage on a Huaweu 3G dongle, you should read the following ticket:Mass storage missing from 3G dongle