Comment # 5 on bug 911347 from Thomas Blume

Thanks for the feedback.
Using relative values for disk space is indeed more sensitive.

The code checks for the filesystem size of the mount where the journal is
stored.
So, this covers a separate /var partition.
Still, it is very hard to estimate an average size for /var.
If it is 1G we would have only 10Mb for the journal if we set SystemMaxUse to
1%.
I guess we'd need an absolute lower limit for small systems and an relative
upper limit for big systems.