Openwrt - Extend disk space for apps

README.md

Instructions for expanding space for openwrt programs. In most cases, 2Gb will be enough. We will install the necessary packages for working with USB devices

root@OpenWrt:~# opkg update
root@OpenWrt:~# opkg install nano kmod-usb-core block-mount kmod-fs-ext4 kmod-usb-storage-extras e2fsprogs blkid

After install fdisk package

root@OpenWrt:~# opkg install fdisk

Insert a flash drive into the router and create partitions

root@OpenWrt:~# fdisk /dev/sda
Welcome to fdisk (util-linux 2.25.2).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.
Command (m for help): m
Help:
  DOS (MBR)
   a   toggle a bootable flag
   b   edit nested BSD disklabel
   c   toggle the dos compatibility flag
  Generic
   d   delete a partition
   l   list known partition types
   n   add a new partition
   p   print the partition table
   t   change a partition type
   v   verify the partition table
  Misc
   m   print this menu
   u   change display/entry units
   x   extra functionality (experts only)
  Save & Exit
   w   write table to disk and exit
   q   quit without saving changes
  Create a new label
   g   create a new empty GPT partition table
   G   create a new empty SGI (IRIX) partition table
   o   create a new empty DOS partition table
   s   create a new empty Sun partition table

Command (m for help): d
Selected partition 1
Partition 1 has been deleted.

Command (m for help): p
Disk /dev/sda: 1.9 GiB, 2013265920 bytes, 3932160 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0xcad4ebea

Command (m for help): n
Partition type
   p   primary (0 primary, 0 extended, 4 free)
   e   extended (container for logical partitions)
Select (default p):
Using default response p.
Partition number (1-4, default 1):
First sector (2048-3932159, default 2048):
Last sector, +sectors or +size{K,M,G,T,P} (2048-3932159, default 3932159): +100M
Created a new partition 1 of type 'Linux' and of size 100 MiB.

Command (m for help): n
Partition type
   p   primary (1 primary, 0 extended, 3 free)
   e   extended (container for logical partitions)
Select (default p):
Using default response p.
Partition number (2-4, default 2):
First sector (206848-3932159, default 206848):
Last sector, +sectors or +size{K,M,G,T,P} (206848-3932159, default 3932159):
Created a new partition 2 of type 'Linux' and of size 1.8 GiB.

Changing the label of the first volume to Linux Swap

Command (m for help): t
Partition number (1,2, default 2): 1
Hex code (type L to list all codes): 82
Changed type of partition 'Linux' to 'Linux swap / Solaris'.

Save Changes

Command (m for help): w
The partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.

We format the second section for data in ext3 (if desired, you can in ext4)

root@OpenWrt:~# mkfs.ext3 /dev/sda2
mke2fs 1.42.12 (29-Aug-2014)
/dev/sda2 contains a ext4 file system
        last mounted on Mon Oct 31 11:04:05 2016
Proceed anyway? (y,n) y
Creating filesystem with 465664 4k blocks and 116640 inodes
Filesystem UUID: ec33af13-8569-471e-a6d3-22b3ba95d6fd
Superblock backups stored on blocks:
        32768, 98304, 163840, 229376, 294912
Allocating group tables: done
Writing inode tables: done
Creating journal (8192 blocks): done
Writing superblocks and filesystem accounting information: done

Preparing a section for swap

root@OpenWrt:~# mkswap /dev/sda1
Setting up swapspace version 1, size = 104853504 bytes
Device     Boot  Start     End Sectors  Size Id Type
/dev/sda1         2048  206847  204800  100M 82 Linux swap / Solaris
/dev/sda2       206848 3932159 3725312  1.8G 83 Linux

After the flash is ready, copy the overlay content to our partion /dev/sda2

mount /dev/sda2 /mnt
tar -C /overlay -cvf - . | tar -C /mnt -xf -
umount /mnt

Let's see uuid disk

root@OpenWrt:~# block info /dev/sda2
/dev/sda2: UUID="08514a99-ab63-43bd-9a99-ac83e0b4f240" NAME="EXT_JOURNAL" VERSION="1.0" TYPE="ext4"

Edit fstab

nano /etc/config/fstab
config 'global'
        option  anon_swap       '0'
        option  anon_mount      '0'
        option  auto_swap       '1'
        option  auto_mount      '1'
        option  delay_root      '5'
        option  check_fs        '0'

config 'mount'
        option  target  '/overlay'
        option  uuid    '08514a99-ab63-43bd-9a99-ac83e0b4f240'
        option  fstype  'ext4'
        option  enabled '1'

config 'swap'
        option  device  '/dev/sda1'
        option  enabled '1'

Save and reboot the router

root@OpenWrt:~# reboot

Look what's out there with the free space

root@OpenWrt:~# df -h
Filesystem                Size      Used Available Use% Mounted on
rootfs                    1.7G      3.4M      1.6G   0% /
/dev/root                 2.5M      2.5M         0 100% /rom
tmpfs                    13.9M     76.0K     13.9M   1% /tmp
/dev/sda2                 1.7G      3.4M      1.6G   0% /overlay
overlayfs:/overlay        1.7G      3.4M      1.6G   0% /
tmpfs                   512.0K         0    512.0K   0% /dev

root@OpenWrt:~# free
             total         used         free       shared      buffers
Mem:         28556        24332         4224           76         3008
-/+ buffers:              21324         7232
Swap:       102396            0       102396

Profit! 👍