Generally on OpenWrt I like to mount a USB flash drive at /root for file and script storage. This is loosely based on various tutorials on the OpenWRT Wiki.
This was tested on a Onion Omega2+, but will probably work on the Omega2. I do not have access to an Omega1 to test it.
opkg update
opkg install fdisk kmod-fs-ext4 e2fsprogs swap-utils block-mount
Some Onion versions show an error when installing kmod-fs-ext4, you should update the the latest if you run into problems.
Then insert your sdcard and find it.
fdisk -l
There will be several entries, you are looking for something like this. I'm using an 8GB SD card, it recognizes it as 7.2 GiB.
Disk /dev/mmcblk0: 7.2 GiB, 7746879488 bytes, 15130624 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
Take note of the /dev/mmcblk0 or whatever yours shows. If you use the wrong one you can screw up your device.
If your SDCARD is currently mounted, you will need to unmount it to modify the partition table.
umount /dev/mmcblk0
If you are not mounted it'll show this error.
umount: can't unmount /dev/mmcblk0: Invalid argument
free
Should display something like this, note the swap currently shows 0 for all entries.
total used free shared buffers cached
Mem: 125764 34096 91668 200 4024 12736
-/+ buffers/cache: 17336 108428
Swap: 0 0 0
You will need to create two partitions on your SDCARD.
If your SDCARD already has a partition, it will show an error, which you can ignore.
fdisk /dev/mmcblk0
This section has several inputs which you'll need to make, I noted them in the code sections with ⟵⟵⟵.
Once in the fdisk program it will prompt you with this. I recommend hitting m to see the commands available.
Command (m for help):
You'll probably want to start with F to determine how much free space you have. I'm using an 8GB SDCARD, it shows:
Command (m for help): F ⟵⟵⟵
Unpartitioned space /dev/mmcblk0: 7.2 GiB, 7745830912 bytes, 15128576 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
Start End Sectors Size
2048 15130623 15128576 7.2G
Next up, create a 2GB swap partition with the n command. You will need to make several entries.
Command (m for help): n ⟵⟵⟵
Partition number (1,2,4-8, default 1): 1 ⟵⟵⟵
Partition type
p primary (0 primary, 0 extended, 4 free)
e extended (container for logical partitions)
Select (default p): p ⟵⟵⟵
Partition number (1-4, default 1): 1 ⟵⟵⟵
First sector (2048-15130623, default 2048): 2048 ⟵⟵⟵
Last sector, +sectors or +size{K,M,G,T,P} (2048-15130623, default 15130623): +2G ⟵⟵⟵
Created a new partition 1 of type 'Linux' and of size 2 GiB.
Now create the partition you'll use for /root, again with the n command, unless you are doing something special, you may just hit enter fore each of the prompts, I marked them anyway.
Command (m for help): n ⟵⟵⟵
Partition type
p primary (1 primary, 0 extended, 3 free)
e extended (container for logical partitions)
Select (default p): p ⟵⟵⟵
Partition number (2-4, default 2): 2 ⟵⟵⟵
First sector (4196352-15130623, default 4196352): 4196352 ⟵⟵⟵
Last sector, +sectors or +size{K,M,G,T,P} (4196352-15130623, default 15130623): 15130623 ⟵⟵⟵
Created a new partition 2 of type 'Linux' and of size 5.2 GiB.
Set the swap partition type to swap with the t command. Again you will need to make several entries.
Command (m for help): t ⟵⟵⟵
Partition number (1,2, default 2): 1 ⟵⟵⟵
Partition type (type L to list all types): 82 ⟵⟵⟵
Changed type of partition 'Linux' to 'Linux swap / Solaris'.
You may now print the partition table with the p command to verify what you have done. It should show something like this.
Command (m for help): p ⟵⟵⟵
Disk /dev/mmcblk0: 7.2 GiB, 7746879488 bytes, 15130624 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: 0x95cb5374
Device Boot Start End Sectors Size Id Type
/dev/mmcblk0p1 2048 4196351 4194304 2G 82 Linux swap / Solaris
/dev/mmcblk0p2 4196352 15130623 10934272 5.2G 83 Linux
If all looks good, write the partition with the w command.
Command (m for help): w ⟵⟵⟵
The partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.
This will drop you back to the shell, run fdisk -l again and you should see your partitions have changed and shows something like this.
Disk /dev/mmcblk0: 7.2 GiB, 7746879488 bytes, 15130624 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: 0x95cb5374
Device Boot Start End Sectors Size Id Type
/dev/mmcblk0p1 2048 4196351 4194304 2G 82 Linux swap / Solaris
/dev/mmcblk0p2 4196352 15130623 10934272 5.2G 83 Linux
Take note of your Linux swap and Linux partition Devices.
Format your Linux partition as ext4.
mkfs.ext4 /dev/mmcblk0p2
This will take a minute and output something like the following.
mke2fs 1.43.3 (04-Sep-2016)
Creating filesystem with 1366784 4k blocks and 342048 inodes
Filesystem UUID: 8d86e910-080a-41f2-b4da-bb66c425fe9d
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736
Allocating group tables: done
Writing inode tables: done
Creating journal (16384 blocks): done
Writing superblocks and filesystem accounting information: done
Unfortunately I'm not certain how to format fat32 for you Windows guys & gals. Normally you'd use mkdosfs, but I'm not sure what package from opkg contains it. I don't use Windows at all any more, so I don't really have much use for fat32.
Format your Linux swap partition and enable the swap.
mkswap /dev/mmcblk0p1
swapon /dev/mmcblk0p1
Again use the free command.
free -k
It should now show your updated swap space.
total used free shared buffers cached
Mem: 125764 30172 95592 200 4028 7488
-/+ buffers/cache: 18656 107108
Swap: 2097148 0 2097148
You may also use the swapon command to show your swap space.
swapon -s
This should display something like this.
Filename Type Size Used Priority
/dev/mmcblk0p1 partition 2097148 0 -1
If you have anything in your /root currently, move it to /tmp.
mkdir /tmp/root_temp
mv /root/* /tmp/root_temp
ls -lah /root
Mount the drive and try writing to it.
mount /dev/mmcblk0p2 /root
cd /root
echo "test" > test.txt
cat test.txt
This should display test. Now you can move your stuff back from /tmp to /root.
mv /tmp/root_temp/* /root
rmdir /tmp/root_temp/
Enable the fstab.
/etc/init.d/fstab enable
Detect the mounts.
block detect > /etc/config/fstab
cat /etc/config/fstab
This should display something similar to this, take note of your uuid, they are always different.
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 'swap'
option device '/dev/mmcblk0p1'
option enabled '0'
config 'mount'
option target '/mnt/mmcblk0p2'
option uuid 'YOUR-UUID-HERE'
option enabled '0'
You'll want to edit the fstab.
vi /etc/config/fstab
Make it look like this.
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 'swap'
option device '/dev/mmcblk0p1'
option enabled '1'
config 'mount'
option target '/root'
option uuid 'YOUR-UUID-HERE'
option enabled '1'
Reboot and exit.
reboot && exit
SSH back into the unit and make sure the mount worked
df -h
Should show something like this.
Filesystem Size Used Available Use% Mounted on
/dev/root 5.5M 5.5M 0 100% /rom
tmpfs 61.4M 184.0K 61.2M 0% /tmp
/dev/mtdblock6 25.1M 3.7M 21.4M 15% /overlay
overlayfs:/overlay 25.1M 3.7M 21.4M 15% /
tmpfs 512.0K 0 512.0K 0% /dev
/dev/mmcblk0p2 5.1G 20.9M 4.8G 0% /root
Then check the swap.
swapon -s
Should still display something like this.
Filename Type Size Used Priority
/dev/mmcblk0p1 partition 2097148 0 -1
You may re-check your free space.
free
Should display something like this.
total used free shared buffers cached
Mem: 125764 35868 89896 200 5256 12732
-/+ buffers/cache: 17880 107884
Swap: 2097148 0 2097148
You are done.
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