Syslog missing logs before reboot

[axeleroy]

Hello there,

 

My board had just rebooted with no notice, so I wanted to take a look at /var/log/syslog in order to diagnose the issue, but for some reason, there are no logs between Dec 30 and the moment my board rebooted.
 

Why are logs missing? What do I need to do in order to keep them the next time my board reboots? Also, am I looking at the right place to diagnose reboots?

Thanks for you help!

 

PS1: My board is the Helios64 and I'm running Armbian 20.11.4 Buster with OMV 5.
PS2: I know there is an Helios64 Club, though I did not choose to post there as I'm not sure if this issue is specific to that board.

[Werner]

18 minutes ago, axeleroy said:

I'm not sure if this issue is specific to that board.

It is not

The reason is that /var/log is mounted as a ramdisk to significantly increase the lifetime of sd card/flash memory due to avoiding lots of small writes to it. The downside is that tracking down issues can be complicated sometimes...

[axeleroy]

That what I thought as I read on the forums that the logs were in ramdisk, but I am confused since syslog had entries from before the reboot, as if there was an exception for this file (though I guess I'm probably wrong).

How can I make the logs persistent, at least temporarily? I also had reboots when trying to backup OMV using openmediavault-backup and dd, I would like to diagnose those too (though I stop using dd in favor of borgbackup).

[Werner]

Go to /etc/default/armbian-ramlog and disable it

[axeleroy]

Great, thank you!