Web Server & NodeRed Failure

[DCLancaster]

We have a RevPi in production and it's been running for 2 months now.
Recently our PLC has been failing to see the RevPi's heartbeat we setup using an output controlled by NodeRed.
Initial steps to diagnose were we could SSH and use RevPi Commander, but we could not access the web interface for the RevPi or NodeRed.
This was when trying to connect directly via IP and port as detailed in the SSH banner.

Code: Select all

$ systemctl --failed
apache2.service, systemd-sysusers.service

Code: Select all

$ /var/log/apache2/error.log
Fatal Error Unable to create lock file: No space left on device

This error occurs around every 15 minutes.

But $df -h shows our disk usage is well within reasonable amounts with 2GB of 6GB being free.
We have yet to try reinstallation with $ sudo apt-get install --reinstall revpi-webstatus pictory; but we are interested to know if anyone has seen something similar?
I have also set up a disk usage logging script to log during production but this has not yet been deplayed yet.

If anyone has seen something similar this would be a massive help as we're unclear what could cause such a disk usage error?
Thank you

[RevPiModIO]

Hi DCLancaster!

The Apache lock file is created in `/run/lock`. This is a tmpfs, which is in the RAM. It could happen that the storage is no longer sufficient due to a high utilization of the RAM.

The utilization of the RAM can be displayed via `free -h`.

If little RAM is available, the SWAP can be activated:
- On a bullseye image via the command `sudo revpi-config enable dphys-swapfile`
- On a bookworm image in cockpit (WebUI) in the menu item "Revolution Pi".

Sven

[DCLancaster]

Brilliant thank you Sven, I have updated my little storage measurement to include high memory usage processes so we should find something on our next visit.

Ideally we should not need swap so I assume we're not clearing our cache from memory and just have not noticed it yet.

Hopefully the cause is us! Thank you again