mmtracectl command

Availability

Available on all IBM Spectrum Scale™ editions.

Description

Results

GPFS tracing can be started, stopped, or related configuration options can be set.

Parameters

--start | --stop | --off | --set | --status

Specifies the actions that the mmtracectl command performs, where:

--start

Starts the trace.

--stop

Stops the trace.

--off

Clears all of the setting variables and stops the trace.

--set

Sets the trace variables.

--status

Displays the tracing status of the specified nodes. This parameter is rejected with a usage error message unless all the nodes in the cluster are running IBM Spectrum Scale 5.0.0 or later.

In the following table, the letter X indicates that the specified type of information is displayed:

Table 1. Tracing status information

Environment	Type of information that is displayed
	Whether tracing is on or off	Kernel mode	Daemon mode
Linux	X	X	X
Windows	X
AIX	X

--trace={io | all | def | "Class Level [Class Level ...]"}

Allows for predefined and user-specified trace levels, where:

io

Indicates trace-level settings tailored for input and output (I/O).

all

Sets trace levels to their highest setting (9).

def

Indicates that the default trace settings will be used.

"Class Level [Class Level ...]"

Specifies a trace class and level.

--trace-recycle={off | local | global | globalOnShutdown}

Controls trace recycling during daemon termination. The following values are recognized:

off

Does not recycle traces. This is the default value until mmtracectl --start is run. If no trace-recycle value has been explicitly set when mmtracectl --start is run, see the following description for local. The mmtracectl --off command will remove any explicit value for trace-recycle, thus effectively setting trace-recycle back to the off value.

local

Recycles traces on the local node when mmfsd goes down abnormally. This setting also starts traces automatically any time that mmstartup is run to start the GPFS daemon, which could include an autoload on a reboot. If there is no trace-recycle value explicitly set at the time that mmtracectl --start is run, mmchconfig will be run to explicitly set the trace-recycle value to local. The starting of the actual tracing will be delayed while that configuration change is being made.

global

Recycles traces on all nodes in the cluster when an abnormal daemon shutdown occurs.

globalOnShutdown

Recycles traces on all nodes in the cluster for normal and abnormal daemon shutdowns.

--aix-trace-buffer-size=BufferSize

Controls the size of the trace buffer in memory for AIX.

--tracedev-buffer-size=BufferSize

Specifies the trace buffer size for Linux trace in blocking mode. If --tracedev-write-mode is set to blocking, this parameter will be used. It should be no less than 4K and no more than 64M. The default is 4M.

Note: This option applies only to Linux nodes.

--trace-file-size=FileSize

Controls the size of the trace file. The default is 128M on Linux and 64M on other platforms.

--trace-dispatch={yes | no}

Enables AIX thread dispatching trace hooks.

--tracedev-compression-level=Level

Specifies the trace raw data compression level. Valid values are 0 to 9. A value of zero indicates no compression. A value of 9 provides the highest compression ratio, but at a lower speed. The default is 6.

Note: This option applies only to Linux nodes.

--tracedev-write-mode={blocking | overwrite}

Specifies when to overwrite the old data, where:

blocking

Specifies that if the trace buffer is full, wait until the trace data is written to the local disk and the buffer becomes available again to overwrite the old data.

overwrite

Specifies that if the trace buffer is full, overwrite the old data. This is the default.

Note: This option applies only to Linux nodes.

--tracedev-timeformat={relative | absolute | calendar}

Controls time formatting in the trace records. The following values are accepted:

relative

Displays the trace time stamp in relative format, showing the number of seconds from the beginning time stamp. This is the default.

absolute

Displays the trace time stamp in absolute format, showing the number of seconds since 1/1/1970.

calendar

Displays the trace time stamp in local calendar format, showing day of the week, month, day, hours, minutes, seconds, and year.

--tracedev-overwrite-buffer-size=Size

Specifies the trace buffer size for Linux trace in overwrite mode. If --tracedev-write-mode is set to overwrite, this parameter will be used. It should be no less than 16M. The default is 64M.

Note: This option applies only to Linux nodes.

--format | --noformat

Enables or disables formatting.

-N {Node[,Node...] | NodeFile | NodeClass}

Specifies the nodes that will participate in the tracing of the file system. This option supports all defined node classes (with the exception of mount). The default value is all.

For general information on how to specify node names, see Specifying nodes as input to GPFS commands.

Exit status

0

Successful completion.

nonzero

A failure has occurred.

Security

You must have root authority to run the mmtracectl command.

The node on which the command is issued must be able to execute remote shell commands on any other node in the cluster without the use of a password and without producing any extraneous messages. For more information, see Requirements for administering a GPFS file system.

See also

See the mmtrace shell script.

Location