[Buildroot] Why is /var/log symlinked to a tmpfs?

[Buildroot] Why is /var/log symlinked to a tmpfs?

[PTaylor.us]

First, I must say that buildroot is a great tool. Thank you.

I am using buildroot branch 2016.11.x.

Why is /var/log a symlink to /tmp (which is mounted with a tmpfs). My
understanding is that */var/log should be persistent across reboots*. I'm
very curious why the default skeleton was setup like this. It is causing
problems, for one, with journald where the "fix" I've seen suggested on this
mailing list is to set the logging to "volatile". 



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[Buildroot] Why is /var/log symlinked to a tmpfs?

[Thomas Petazzoni]

Hello,

On Sun, 14 May 2017 05:00:00 -0700 (PDT), PTaylor.us wrote:
> First, I must say that buildroot is a great tool. Thank you.
> 
> I am using buildroot branch 2016.11.x.
> 
> Why is /var/log a symlink to /tmp (which is mounted with a tmpfs). My
> understanding is that */var/log should be persistent across reboots*. I'm
> very curious why the default skeleton was setup like this. It is causing
> problems, for one, with journald where the "fix" I've seen suggested on this
> mailing list is to set the logging to "volatile". 

The reason why /var/log is a symlink to a tmpfs is because we want to
support the root filesystem to be mounted read only.

We know the current skeleton has some issues with journald (see
https://bugs.busybox.net/show_bug.cgi?id=7892), and Yann E. Morin is
working on a patch series to address this, see:

  https://git.buildroot.org/~ymorin/git/buildroot/log/?h=yem/systemd-skeleton
  https://git.buildroot.org/~ymorin/git/buildroot/log/?h=yem/systemd-skeleton-2

Best regards,

Thomas
-- 
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com