Comment 0 for bug 1618188

After upgrading 14.04 -> 16.04, key services are now running on systemd and using the systemd journal for logging. In 14.04, key system logs like /var/log/messages and /var/log/syslog were persistent, but after the upgrade to 16.04 there has a been a regression of sorts: Logs sent to systemd's journald are now being thrown away during reboots.

This behavior is controlled by the `Storage=` option in `/etc/systemd/journald.conf`. The default setting is `Storage=auto` which will persist logs in `/var/log/journal/`, *only if the directory already exists*. But the directory was not created as part of the 14.04 -> 16.04 upgrade, so logging was being lost for a while before I realized what was happening.

This issue could be solved by either creating /var/log/journal or changing the default Storage behavior to `Storage=persistent`, which would create the directory if need be.

## Related reference

 * `systemd` currently compounds the issue by having ["journal --disk-usage" report memory usage as disk usage](https://github.com/systemd/systemd/issues/4059), giving the impression that the disk is being used for logging when it isn't.
 * [User wonders where to find logs from previous boots, unaware that the logs were thrown away](http://askubuntu.com/questions/765315/how-to-find-previous-boot-log-after-ubuntu-16-04-restarts)

## Recommended fix

Restoring persistent logging as the default is recommended.