fstrace d [-se <set name>+] [-fo <log name>]
[-fi <output filename>] [-sl <seconds between reads>]
The fstrace dump command displays the current contents of the "cmfx"
trace log on the standard output stream or writes it to the file named by
the -file argument.
To write the log continuously to the standard output stream or to a file,
use the -follow argument. By default, the log's contents are written
out every ten seconds and then automatically cleared. To change the
interval between writes, use the -sleep argument.
This command produces output only if the "cm" event set is active. To
display or set the event set's state, use the fstrace lsset or
fstrace setset command respectively.
To make the output from this command maximally readable, the message
catalog file called afszcm.cat must reside in the local
/etc/openafs/C directory. If necessary, copy the file to that
directory from the AFS Binary Distribution before activating tracing.
When the "cm" event set is active, a defined amount of kernel memory (by
default, 60 KB) is allocated for the "cmfx" trace log. As described in
fstrace(8), when the buffer is full, messages are overwritten in a
circular fashion (new messages overwrite the oldest ones). To allocate
more kernel memory for the log, use the fstrace setlog command; to
display the log buffer's current size, use the fstrace lslog command
with the -long argument.
-set <set name>+
Names the event set for which to write out the associated trace log. The
only acceptable value is "cm" (for which the associated trace log is
"cmfx"). Provide either this argument or the -log argument, or omit
both to write out the "cmfx" log by default.
-follow <log name>
Names the trace log to write out continuously at a specified interval (by
default, every ten seconds; use the -sleep argument to change the
interval). The log is cleared after each write operation.
The only acceptable value is "cmfx". Provide either this argument or the
-set argument, or omit both to write out the "cmfx" log by default.
-file <output filename>
Specifies the pathname of the file to which to write the trace log's
contents. It can be in AFS or on the local disk. Partial pathnames are
interpreted relative to the current working directory. If this argument is
omitted, the trace log appears on the standard output stream.
-sleep <seconds between reads>
Sets the number of seconds between writes of the trace log's contents when
it is dumped continuously. Provide the -follow argument along with this
one. If this argument is omitted, the default interval is ten seconds.
Prints the online help for this command. All other valid options are
The output begins with a header specifying the date and time at which the
write operation began. If the -follow argument is not included, the
header also reports the number of logs being dumped; it is always 1,
since there is only the "cmfx" trace log. The format of the header is as
AFS Trace Dump -
Found 1 logs.
Contents of log cmfx:
Each subsequent message describes a Cache Manager operation in the
time <timestamp>, pid <pid>:<event_message>
Specifies the time at which the Cache Manager performed the operation, as
the number of seconds since the dump began.
Specifies the process ID of the process or thread associated with the
Is the message itself. They are generally meaningful only to someone
familiar with the AFS source code.
In addition, every 1024 seconds the fstrace command interpreter writes a
message that records the current clock time, in the following format:
time <timestamp>, pid <pid>: Current time: <unix_time>
Is the number of seconds from the start of trace logging.
Is the process ID number.
Is the machine's clock time, represent in the standard UNIX time format as
the number of seconds since midnight on January 1, 1970.
Use this message to determine the actual clock time associated with each
log message. Determine the actual time as follows:
Locate the message of interest.
Search backward through the trace file for the closest current time
If the current time message's timestamp is smaller than the log message's
timestamp, subtract former from the latter. If the current time message's
timestamp is larger than the log message's timestamp, add 1024 to the
latter and subtract the former from the result.
Add the resulting number to the current time message's <unix_time> to
determine the log message's actual time.
If any of the data in the kernel trace buffer has been overwritten since
tracing was activated, the following message appears at the appropriate
place in the output:
Log wrapped; data missing.
To reduce the likelihood of overwriting, use the fstrace setlog command
to increase the kernel buffer's size. To display the current defined
buffer size, use the fstrace lslog command with the -long argument.
The following message at the end of the log dump indicates that it is
AFS Trace Dump - Completed
The following command dumps the log associated with the cm event set to
the standard output stream.
# fstrace dump -set cm
AFS Trace Dump -
Date: Tue Apr 7 10:54:57 1998
Found 1 logs.
time 32.965783, pid 0: Tue Apr 7 10:45:52 1998
time 32.965783, pid 33657: Close 0x5c39ed8 flags 0x20
time 32.965897, pid 33657: Gn_close vp 0x5c39ed8 flags 0x20 (returns 0x0)
time 35.159854, pid 10891: Breaking callback for 5bd95e4 states 1024 (volume 0)
time 35.407081, pid 10891: Breaking callback for 5c0fadc states 1024 (volume 0)
time 71.440456, pid 33658: Lookup adp 0x5bbdcf0 name g3oCKs \
fid (756 4fb7e:588d240.2ff978a8.6)
time 71.440569, pid 33658: Returning code 2 from 19
time 71.440619, pid 33658: Gn_lookup vp 0x5bbdcf0 name g3oCKs (returns 0x2)
time 71.464989, pid 38267: Gn_open vp 0x5bbd000 flags 0x0 (returns 0x0)
AFS Trace Dump - Completed
The following command dumps the trace log associated with the cm event set
on the local machine to the file "cmfx.dump.file.1", using the default
interval of 10 seconds between successive dumps:
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