Background:
An embedded Linux device has a very small main disk size (less then 2GB), and a larger external flash memory (SATA disk of size 64GB).
Issue:
Some of the applications run by systemd (and logged by journald) produce very large log files, in excess of 10GB that need to be recorded. The embedded device is not connected to any external network for long periods so must be able to store logs for these long extended periods. Therefore log files can reach in excess of 10GB, filling the disk. The vacuum function of journald cannot be used as it would clear logs from early in the device run history - which are important for failure analysis systems.
Question(s):
How to have journald use the external disk for logging files?
What is the best way to achieve this (mount over /var/log/journal?)
Would it better to use the forward to function of journald to send them to a separate service that logged them to the external disk?
