Comment 12 for bug 1790205

So, as has been previously stated here, and as is documented in section 5 of the journald.conf man page (install man-db, run 'man 5 journald.conf'), journald will, by default, limit the journals' disk allocation to either a maximum of 10% of available disk space, or to the absolute size of 4GB, whichever is lower.

Example 1: You have a 120 GB disk, 70 GB are in use, leaving 50 GB. 10% of 50 GB are 5 GB, but the absolute value of 4 GB is lower, so journald will at most take 4 GB storage on this system (and dynamically less, if the disk grows fuller).

Example 2: You have a 20 GB disk, 12 GB are in use, leaving 8 GB. 10% of 8 GB are 800 MB, which is less than 4 GB, so journald will at most take 800 MB storage on this system (and dynamically more or less, if disk allocation changes).

Benjamin is now reporting 4.1 GB allocated, which is more than 4 GB, and with the details above, this is unexpected. What could be the reason? These limits are applied both when journald starts, and when vacuuming takes place. So if Benjamins' logs have grown by 100 MB since journald started, this can easily explain this situation. They will be reduced to 4 GB (or less, if the disk runs full) again next time vacuuming takes place (such as when journald is restarted).

So unless these limits are considered a problem (why? disk space is cheap, and you can modify them as needed if you're on a special (embedded?) platform), I don't see a problem here.