NAME

       trace-cmd-restore - restore a failed trace record

SYNOPSIS

       trace-cmd restore [OPTIONS] [command] cpu-file [cpu-file ...]

DESCRIPTION

       The trace-cmd(1) restore command will restore a crashed trace-cmd-record(1) file. If for
       some reason a trace-cmd record fails, it will leave a the per-cpu data files and not
       create the final trace.dat file. The trace-cmd restore will append the files to create a
       working trace.dat file that can be read with trace-cmd-report(1).

       When trace-cmd record runs, it spawns off a process per CPU and writes to a per cpu file
       usually called trace.dat.cpuX, where X represents the CPU number that it is tracing. If
       the -o option was used in the trace-cmd record, then the CPU data files will have that
       name instead of the trace.dat name. If a unexpected crash occurs before the tracing is
       finished, then the per CPU files will still exist but there will not be any trace.dat file
       to read from. trace-cmd restore will allow you to create a trace.dat file with the
       existing data files.

OPTIONS

       -c
           Create a partial trace.dat file from the machine, to be used with a full trace-cmd
           restore at another time. This option is useful for embedded devices. If a server
           contains the cpu files of a crashed trace-cmd record (or trace-cmd listen), trace-cmd
           restore can be executed on the embedded device with the -c option to get all the
           stored information of that embedded device. Then the file created could be copied to
           the server to run the trace-cmd restore there with the cpu files.

               If *-o* is not specified, then the file created will be called
               'trace-partial.dat'. This is because the file is not a full version
               of something that trace-cmd-report(1) could use.

       -t tracing_dir
           Used with -c, it overrides the location to read the events from. By default, tracing
           information is read from the debugfs/tracing directory.  -t will use that location
           instead. This can be useful if the trace.dat file to create is from another machine.
           Just tar -cvf events.tar debugfs/tracing and copy and untar that file locally, and use
           that directory instead.

       -k kallsyms
           Used with -c, it overrides where to read the kallsyms file from. By default,
           /proc/kallsyms is used.  -k will override the file to read the kallsyms from. This can
           be useful if the trace.dat file to create is from another machine. Just copy the
           /proc/kallsyms file locally, and use -k to point to that file.

       -o output'
           By default, trace-cmd restore will create a trace.dat file (or trace-partial.dat if -c
           is specified). You can specify a different file to write to with the -o option.

       -i input
           By default, trace-cmd restore will read the information of the current system to
           create the initial data stored in the trace.dat file. If the crash was on another
           machine, then that machine should have the trace-cmd restore run with the -c option to
           create the trace.dat partial file. Then that file can be copied to the current machine
           where trace-cmd restore will use -i to load that file instead of reading from the
           current system.

EXAMPLES

       If a crash happened on another box, you could run:

           $ trace-cmd restore -c -o box-partial.dat

       Then on the server that has the cpu files:

           $ trace-cmd restore -i box-partial.dat trace.dat.cpu0 trace.dat.cpu1

       This would create a trace.dat file for the embedded box.

SEE ALSO

       trace-cmd(1), trace-cmd-record(1), trace-cmd-report(1), trace-cmd-start(1),
       trace-cmd-stop(1), trace-cmd-extract(1), trace-cmd-reset(1), trace-cmd-split(1),
       trace-cmd-list(1), trace-cmd-listen(1)

AUTHOR

       Written by Steven Rostedt, <rostedt@goodmis.org[1]>

RESOURCES

       git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/trace-cmd.git

COPYING

       Copyright (C) 2010 Red Hat, Inc. Free use of this software is granted under the terms of
       the GNU Public License (GPL).

NOTES

        1. rostedt@goodmis.org
           mailto:rostedt@goodmis.org

                                            03/23/2020                       TRACE-CMD-RESTORE(1)