More system disk space using pivot-overlay (and pivot-root) on the Omega2

Kit Bishop

Using pivot-overlay (or pivot-root) on a USB drive is a good way to give yourself more usable system disk space. There has recently been some communication about this for the Omega2

When attempting to follow the Omega1 instructions at https://wiki.onion.io/Tutorials/Using-USB-Storage-as-Rootfs problems have arisen over the ability to install the block-mount package and it has been surmised (by me as well as others :-() that a different method was needed for the Omega2

I can now indicate that the original Omega1 instructions as above work so long as you do the following to get block-mount: This is all using the latest system image 0.1.8 b451:

Edit the file /etc/opkg/distfeeds.conf and un-comment the line:

src/gz reboot_core http://downloads.lede-project.org/snapshots/targets/ramips/mt7688/packages

After making this change, re run:
```
opkg update
opkg install block-mount
```

Then the instructions in https://wiki.onion.io/Tutorials/Using-USB-Storage-as-Rootfs work fine on the Omega2 - I've done all this and it works

I also have no reason to believe that this would not also work with an SD card.

Mikael Djurfeldt

@Kit-Bishop I can confirm that this works also with the sdcard on Omega2+ (using firmware 0.1.8.b145).

Kit Bishop

@Mikael-Djurfeldt Cool Thanks - good to know it works

ExplosiveSoda

As far as I can tell, this doesn't work with an sd card. Hopefully the documentation for it comes soon.
https://community.onion.io/topic/1282/omega2-reboot-and-sd-card-fixed

Edit: Actually I think it did work. I'm not entirely sure though. I did the exroot with pivot-root with my SD card. Before I started I created a partition that was formatted in ext4. I can still use my omega fine and install things. I'm curious if the storage is supposed to update on the local UI. Right now it still says 31MB and everything I have installed so far is increasing in that section. Not sure if it will become full once I reach 31MB or if it will just continue.

Edit 2: It didn't work. Guess I will wait until they create an SD card documentation.

Leo de Blaauw

actually install block-mount won't work anymore omega2, firmware 1.9 will just report not installing just use sbin/block instead...

Ok, so is there any other way to get my hands on swapon ?

regards,
Leo

Kit Bishop

@Leo-de-Blaauw When you install block-mount using the instructions I gave above, ignore any message about just use sbin/block instead - I was initially puzzled by this, after some experimentation, it was clear that the install had worked - I don't know why one gets such a message, but all is good ater the install.

Leo de Blaauw

@Kit-Bishop true found swapon in usr/sbin eventually and working fine now. Now if node-red wouldnt give me memory segmentation errors i would be truly happy...

Steven de Salas

Hi guys,

Aparently there is an official guide in the docs for pivot-overlay (v0.1.9 b149 and up).

See link below:

Booting from External Storage
https://docs.onion.io/omega2-docs/boot-from-external-storage.html

I can confirm this works with the SD card in the Omega2+ (using b149). There was an odd error message Configuring block-mount... this file has been obsoleted. please call /sbin/block mount directly but I just ignored it and carried on.

This is what I get now with my 8GB Sandisk:

root@Omega-72FF:~# df -h
Filesystem                Size      Used Available Use% Mounted on
/dev/root                 5.5M      5.5M         0 100% /rom
tmpfs                    61.4M    752.0K     60.7M   1% /tmp
/dev/mmcblk0p1            7.2G     91.9M      6.7G   1% /overlay
overlayfs:/overlay        7.2G     91.9M      6.7G   1% /
tmpfs                   512.0K         0    512.0K   0% /dev

Adrian Rix

Did work for me too (b152)

Also have 8Gb via SD now

Costas Costas

Any chance we can safely power off the Omega's now we are using SD cards for the overlay?

Chris Stratton

@Costas-Costas said in More system disk space using pivot-overlay (and pivot-root) on the Omega2:

Any chance we can safely power off the Omega's now we are using SD cards for the overlay?

You would need to make sure the shutdown process unmounted them first.

That's pretty standard Linux historic behavior since it's an issue for disks too so it shouldn't be too hard to activate; it might already be handled, you'd have to see.

The more challenging problem to solve is the risk of unexpected shutdowns when someone bumps the plug, or even intentionally pulls it.

Armstead Smith

@Kit-Bishop
Thanks for this. However, I tried it and the tar extract fails with
tar: can't open './upper/usr/lib/libncursesw.so.6.0': File exists
How can I get past this?

Armstead Smith

@Armstead-Smith
Ahh. The USB wasn't ext4. It works now!