Provided by: ledmon_0.95-2_amd64 bug


       ledmon - Intel(R) LED monitor service for storage enclosures.


       ledmon [OPTIONS]


       The ledmon application is a daemon process used to monitor a state of software RAID
       devices (md only) or a state of block devices. The state is visualizing on LEDs associated
       to each slot in an enclosure or a drive bay. There are two types of system: 2-LEDs system
       (Activity LED, Status LED) and 3-LEDs system (Activity LED, Locate LED, Fail LED). This
       application has the highest priority when accessing the LEDs.

       The ledmon application supports LED management of the SAS/SATA and PCIe storages.

       Supported protocols/methods for LED management are:

       •   SES-2 and SMP for SAS devices,

       •   LED messages over SGPIO for SATA,

       •   VMD and NPEM for PCIe.

       SAF-TE protocol is not supported.

       For SAS/SATA storages supporting controllers may transmit LED management information to
       the backplane controllers via the SGPIO interface. The SGPIO bus carries bit patterns,
       which translate into LED blink patterns in accordance with the International Blinking
       Pattern Interpretation (IBPI) of SFF-8489 specification for SGPIO.  Please note some
       enclosures do not stick close to the SFF-8489 specification. It might happen that the
       enclosure processor will accept the IBPI pattern but it will blink LEDs not according to
       SFF-8489 specification or it has a limited number of patterns supported.

       For more information about communication methods please consult the appropriate

       There's no method provided to specify which RAID volume should be monitored and which not.
       The ledmon application monitors all RAID devices and visualizes their state.

       The ledmon application has been verified to work with Intel(R) storage controllers (i.e.
       Intel(R) AHCI controller and Intel(R) SAS controller).  The application might work with
       storage controllers of other vendors (especially SAS/SCSI controllers). However storage
       controllers of other vendors have not been tested.

       The ledmon application is part of Intel(R) Enclosure LED Utilities. Only single instance
       of the application is allowed.

       The ledmon utilizes the following documents as references:

       •   SGPIO (Serial GPIO) - SFF-8485

       •   IBPI (International Blinking Pattern Interpretation) - SFF-8489

       •   LED Enclosure management messages - AHCI specification rev 1.3, section 12.2.1.

       •   SAS (Serial Attached SCSI) - T10/1760-D

       •   SES-2 (SCSI Enclosure Services-2) - T10/1559-D

       •   SMP (Serial Management Protocol) - T10/1760-D

       •   NPEM (Native PCIe Enclosure Management) - PCIe base specification rev 4.0

       •   VMD (Intel(R) Volume Management Device) - Intel(R) VROC (VMD NVMe RAID) Quick
           Configuration Guide rev 1.2


       -c or --config=path
               Sets a path to local configuration file. If this option is specified the global
               configuration file and user configuration file has no effect.

       -l or --log=path
               Sets a path to local log file. If this option is specified the global log file
               /var/log/ledmon.log is not used.

       -t or --interval=seconds
               Sets time interval between scans of sysfs. The value is given in seconds.  The
               minimum is 5 seconds the maximum is not specified.

       --quiet or --error or --warning or --info or --debug or --all
               Verbose level - 'quiet' means no logging at all and 'all' means to log everything.
               The levels are given in order. If user specifies more then one verbose option the
               last option comes into effect. The default level is 'warning'. Verbose level also
               can be set by --log-level=level.

               Run process foreground instead of a daemon. This option is useful in systemd
               service file. Another use case of this option is debugging with elevated

       -h or --help
               Prints this text out and exits.

       -v or --version
               Displays version of ledmon and information about the license and exits.


               Global log file, used by ledmon application. To force logging to user defined file
               use -l option switch.

               Global configuration file, shared between ledmon and all ledctl application
               instances. Local configuration file can be used by running ledmon with -c switch.


       Copyright (c) 2009-2021 Intel Corporation.

       This program is distributed under the terms of the GNU General Public License as published
       by the Free Software Foundation. See the build-in help for details on the License and the
       lack of warranty.


       The ledmon application does not recognize PFA state (Predicted Failure Analysis), hence
       the PFA pattern from SFF-8489 specification is not visualized.


       ledctl(8), ledmon.conf(5)


       This manual page was written by Artur Wojcik <>. It may be used by