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.
