...
This project employs the logging facade SLF4J, using Apache Log4j 2.x as its backend. Accordingly, levels of detail can be specified as follows:
OFF:
...
The
...
highest
...
possible
...
rank
...
and
...
is
...
intended
...
to
...
turn
...
off
...
logging.
...
ERROR:
...
Designates
...
error
...
events
...
that
...
might
...
still
...
allow
...
the
...
application
...
to
...
continue
...
running.
...
WARN:
...
Designates
...
potentially
...
harmful
...
situations.
...
INFO:
...
Designates
...
informational
...
messages
...
that
...
highlight
...
the
...
progress
...
of
...
the
...
application
...
at
...
coarse-grained
...
level.
...
DEBUG:
...
Designates
...
fine-grained
...
informational
...
events
...
that
...
are
...
most
...
useful
...
to
...
debug
...
an
...
application.
...
TRACE:
...
Designates
...
finer-grained
...
informational
...
events
...
than
...
the
...
DEBUG.
...
ALL:
...
All
...
levels
...
including
...
custom
...
levels.
...
For more guidance on which level to use, see Coding Conventions#Logging
For modifying the log output of a running client, you may use a custom log4j config file by setting a system property at startup. Besu's logging doc provides good documentation on how to configure logging in Besu.