How to extend WeIO flash space - nodesign/weio GitHub Wiki
How to extend WeIO flash space
Even if the flash space on WeIO is sufficient for most applications, when new python packages must be installed, or when the applications assets are important, the flash space available can fast become a problem.
To solve this problem, WeIO version 1.2 (and above) can be extended to a SD Card. This allow to increase the flash space from few megabytes to several gigabytes, depending of the SD card capacity.
Obviously, once the system is extended, the SD card must always stay plugged. Without it, the system will not boot anymore. Moreover, the future system updates will squash it and you will need to extend your system again.
Pre-requisities
Before trying to extend your system, be sure to be able to connect to the board via the debug console.
For Linux and OSX, this can be done with screen :
screen /dev/ttyUSBx 115200 8N1 under Linux systems, or screen /dev/tty.usbxxxxxx 115200 8N1 under OSX.
On Windows system, PuTTY is known to work well.
You also need an empty SD Card. If the SD Card is not empty, it will be erased during the processus. The filesystem in which the SD Card is formatted is not important.
Prepare the system
To extend the root filesystem, it's strongly recommended to insert only the SD Card. All other external storage devices (USB HDD or USB Flash) must be disconnected of WeIO.
Via the debug console, connect to the board (and if needed, press enter) : the banner should be displayed :
## ## ######## #### #######
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WEIO Web Of Things Platform
Copyright (C) 2013-2015 Nodesign.net,
Uros PETREVSKI, Drasko DRASKOVIC
All rights reserved
root@WEIO:/#
By default, removable devices are automatically mounted under /weioUser/. To control that your SD Card is correctly detected and mounted, you can type the command :
root@WEIO:/# df
Filesystem 1K-blocks Used Available Use% Mounted on
rootfs 3904 312 3592 8% /
/dev/root 11264 11264 0 100% /rom
tmpfs 30812 276 30536 1% /tmp
/dev/mtdblock5 3904 312 3592 8% /overlay
overlayfs:/overlay 3904 312 3592 8% /
tmpfs 512 0 512 0% /dev
/dev/sda1 3863720 8036 3639700 0% /weioUser/sd
The SD Card (/dev/sda1) is currently mounted on weioUser/sd.
The process that automatically check for removable device and mount them must be stopped :
root@WEIO:/# /etc/init.d/usd stop
And the SD Card can be unmounted :
root@WEIO:/# umount /weioUser/sd/
root@WEIO:/# rm -r /weioUser/sd # Manually remove the mountpoint
Extend the system
At this point, the SD Card can be prepared. The first step is to format it :
root@WEIO:/# mkfs.ext4 -F /dev/sda1
Once formatted, the SD Card can be mounted under /mnt
root@WEIO:/# mount /dev/sda1 /mnt/
Now we can setup the system to use the SD Card :
block detect > /etc/config/fstab
You'll now have to manually edit /etc/config/fstab, with nano or vi :
root@WEIO:/# vi /etc/config/fstab
The file will looks like :
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 '/mnt/sda1'
option uuid '0824a446-69a1-405a-b856-b276102fa6db'
option enabled '0'
The SD Card must be mounted on /overlay during the boot process. To do that, the file must be edited that way :
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 '0824a446-69a1-405a-b856-b276102fa6db'
option enabled '1'
Then, save the file.
Now, the content of /overlay must be copied on the SD Card :
root@WEIO:/# tar -C /overlay -cvf - . | tar -C /mnt -xf -
And finally, the SD Card can be unmounted :
root@WEIO:/# umount /mnt/
The system is now ready. You can reboot the system :
root@WEIO:/# reboot
When the system has finished to boot, you can check that the system has been extended :
root@WEIO:/# df -h
Filesystem Size Used Available Use% Mounted on
rootfs 3.7G 7.8M 3.5G 0% /
/dev/root 11.0M 11.0M 0 100% /rom
tmpfs 30.1M 32.0K 30.1M 0% /tmp
/dev/sda1 3.7G 7.8M 3.5G 0% /overlay
overlayfs:/overlay 3.7G 7.8M 3.5G 0% /
tmpfs 512.0K 0 512.0K 0% /dev
In my case, I have now 3.5GB of free space !
Adding virtual RAM
WeIO has 64Mb of physical RAM and sometimes this is not enough. In these cases it's possible to allocate additional space on the hard drive and use it as RAM. For that purpose that space must be specially formated, as partition or as file. Here will be explained how to use one file as swap space. Virtual memory in jargon is called swap space. You can read more about here : https://www.centos.org/docs/5/html/5.2/Deployment_Guide/s1-swap-what-is.html
root@WEIO:/# opkg install swap-utils
root@WEIO:/# dd if=/dev/zero of=/swapfile bs=1024 count=1023996 # Create a 1GB swap file at /swapfile (1024*1000Mb = 1023996)
Be patient this procedure will take long. Bigger the file longer time to wait. When finished tell Linux to use this file as partition
root@WEIO:/# mkswap /swapfile
Update fstab configuration file so Linux will know where is swap file in the future
root@WEIO:/# vi /etc/config/fstab
Add this section at the end of file
# a swap file
config 'swap'
option device '/swapfile'
option enable '1'
Restart fstab
root@WEIO:/# /etc/init.d/fstab restart
If you want to check if your system is using properly swap ram, run some application that needs a lot of ram and then check swap usage
root@WEIO:~# swapon -s
Filename Type Size Used Priority
/swapfile file 1023996 3744 -1