9 How to Customize Traces

TRAMP messages are raised with verbosity levels ranging from 0 to 10. TRAMP does not display all messages; only those with a verbosity level less than or equal to tramp-verbose.

The verbosity levels are

•  0 Silent (no TRAMP messages at all)
•  1 Errors
•  2 Warnings
•  3 Connection to remote hosts (default verbosity)
•  4 Activities
•  5 Internal
•  6 Sent and received strings
•  7 Connection properties
•  8 File caching
•  9 Test commands
• 10 Traces (huge)
• 11 Call traces (maintainer only)

With tramp-verbose greater than or equal to 4, messages are also written to a TRAMP debug buffer. Such debug buffers are essential to bug and problem analyzes. For TRAMP bug reports, set the tramp-verbose level to 6 (see Reporting Bugs and Problems).

The debug buffer is in Outline Mode. In this buffer, messages can be filtered by their level. To see messages up to verbosity level 5, enter C-u 6 C-c C-q.

TRAMP handles errors internally. Hence, to get a Lisp backtrace, the following settings are required:

(setq debug-on-error t
      debug-on-signal t)

If tramp-verbose is greater than or equal to 10, Lisp backtraces are also added to the TRAMP debug buffer in case of errors.

In very rare cases it could happen, that TRAMP blocks Emacs. Killing Emacs does not allow inspecting the debug buffer. In that case, you can instruct TRAMP to mirror the debug buffer to a file:

(customize-set-variable 'tramp-debug-to-file t)

The debug buffer is written as a file in your temporary-file-directory, which is usually /tmp/. Use this option with care, because it could decrease the performance of TRAMP actions.

If tramp-verbose is greater than or equal to 11, TRAMP function call traces are written to a TRAMP trace buffer.