Clear Journal
Sometimes you need to clear the journal to clear disk space on a host. Below are some examples of commands to clear the journal.
Examples
Retain the last 100MB of data
Retain the last 10 days of data
Parameter Explanation
The following can be found while running man journalctl
--vacuum-size=, --vacuum-time=, --vacuum-files=
Removes the oldest archived journal files until the disk space they use
falls below the specified size (specified with the usual "K", "M", "G" and
"T" suffixes), or all archived journal files contain no data older than
the specified timespan (specified with the usual "s", "m", "h", "days",
"months", "weeks" and "years" suffixes), or no more than the specified
number of separate journal files remain. Note that running --vacuum-size=
has only an indirect effect on the output shown by --disk-usage, as the
latter includes active journal files, while the vacuuming operation only
operates on archived journal files. Similarly, --vacuum-files= might not
actually reduce the number of journal files to below the specified number,
as it will not remove active journal files.
--vacuum-size=, --vacuum-time= and --vacuum-files=
may be combined in a
single invocation to enforce any combination of a size, a time and a
number of files limit on the archived journal files. Specifying any of
these three parameters as zero is equivalent to not enforcing the specific
limit, and is thus redundant.