12 Storage enclosure LED utilities for MD software RAIDs #
Storage enclosure LED Monitoring utility (ledmon
) and
LED Control (ledctl
) utility are Linux user space
applications that use a broad range of interfaces and protocols to control
storage enclosure LEDs. The primary usage is to visualize the status of
Linux MD software RAID devices created with the mdadm utility. The
ledmon
daemon monitors the status
of the drive array and updates the status of the drive LEDs. The
ledctl
utility allows you to set LED patterns for
specified devices.
These LED utilities use the SGPIO (Serial General Purpose Input/Output) specification (Small Form Factor (SFF) 8485) and the SCSI Enclosure Services (SES) 2 protocol to control LEDs. They implement the International Blinking Pattern Interpretation (IBPI) patterns of the SFF-8489 specification for SGPIO. The IBPI defines how the SGPIO standards are interpreted as states for drives and slots on a backplane and how the backplane should visualize the states with LEDs.
Some storage enclosures do not adhere strictly to the SFF-8489 specification. An enclosure processor might accept an IBPI pattern but not blink the LEDs according to the SFF-8489 specification, or the processor might support only a limited number of the IBPI patterns.
LED management (AHCI) and SAF-TE protocols are not supported by the
ledmon
and ledctl
utilities.
The ledmon
and
ledctl
applications have been verified to work with Intel
storage controllers such as the Intel AHCI controller and Intel SAS
controller. They also support PCIe-SSD (solid-state drive) enclosure LEDs to
control the storage enclosure status (OK, Fail, Rebuilding) LEDs of PCIe-SSD
devices that are part of an MD software RAID volume. The applications might
also work with the IBPI-compliant storage controllers of other vendors
(especially SAS/SCSI controllers); however, other vendors’ controllers have
not been tested.
ledmon
and ledctl
are part of the ledmon
package,
which is not installed by default. Run sudo zypper in
ledmon
to install it.
12.1 The storage enclosure LED monitor service #
The ledmon
application is a daemon
process that constantly monitors the state of MD software RAID devices or
the state of block devices in a storage enclosure or drive bay. Only a
single instance of the daemon should be running at a time. The
ledmon
daemon is part of Intel
Enclosure LED Utilities.
The state is visualized on LEDs associated with each slot in a storage array enclosure or a drive bay. The application monitors all software RAID devices and visualizes their state. It does not provide a way to monitor only selected software RAID volumes.
The ledmon
daemon supports two types
of LED systems: A two-LED system (Activity LED and Status LED) and a
three-LED system (Activity LED, Locate LED, and Fail LED). This tool has the
highest priority when accessing the LEDs.
To start ledmon
, enter
>
sudo
ledmon [options]
where [options] is one or more of the following:
ledmon
#-c PATH
,--confg=PATH
The configuration is read from
~/.ledctl
or from/etc/ledcfg.conf
if existing. Use this option to specify an alternative configuration file.Currently this option has no effect, since support for configuration files has not been implemented yet. See
man 5 ledctl.conf
for details.- -l PATH , --log=PATH
Sets a path to local log file. If this user-defined file is specified, the global log file
/var/log/ledmon.log
is not used.-t SECONDS
,--interval=SECONDS
Sets the time interval between scans of
sysfs
. The value is given in seconds. The minimum is 5 seconds. The maximum is not specified.--quiet
,--error
,--warning
,--info
,--debug
,--all
Specifies the verbosity level. The level options are specified in the order of no information to the most information. Use the
--quiet
option for no logging. Use the--all
option to log everything. If you specify more than one verbose option, the last option in the command applies.-h
,--help
Prints the command information to the console, then exits.
-v
,--version
Displays version of
ledmon
and information about the license, then exits.
The ledmon
daemon does not recognize the PFA (Predicted
Failure Analysis) state from the SFF-8489 specification. Thus, the PFA
pattern is not visualized.
12.2 The storage enclosure LED control application #
The Enclosure LED Application (ledctl
) is a user space
application that controls LEDs associated with each slot in a storage
enclosure or a drive bay. The ledctl
application is a
part of Intel Enclosure LED Utilities.
When you issue the command, the LEDs of the specified devices are set to a
specified pattern and all other LEDs are turned off. This application needs
to be run with root
privileges. Because the
ledmon
application has the
highest priority when accessing LEDs, some patterns set by
ledctl
might have no effect if the
ledmon
daemon is running (except for
the Locate pattern).
The ledctl
application supports two types of LED systems:
A two-LED system (Activity LED and Status LED) and a three-LED system
(Activity LED, Fail LED, and Locate LED).
To start ledctl
, enter
>
sudo
[options] PATTERN_NAME=list_of_devices
where [options] is one or more of the following:
-c PATH
,--confg=PATH
Sets a path to local configuration file. If this option is specified, the global configuration file and user configuration file have no effect.
- -l PATH , --log=PATH
Sets a path to local log file. If this user-defined file is specified, the global log file
/var/log/ledmon.log
is not used.--quiet
Turns off all messages sent to
stdout
orstderr
out. The messages are still logged to local file and thesyslog
facility.-h
,--help
Prints the command information to the console, then exits.
-v
,--version
Displays version of
ledctl
and information about the license, then exits.
12.2.1 Pattern names #
The ledctl
application accepts the following names for
argument, according to the SFF-8489
specification.
locate
Turns on the Locate LED associated with the specified devices or empty slots. This state is used to identify a slot or drive.
locate_off
Turns off the Locate LED associated with the specified devices or empty slots.
normal
Turns off the Status LED, Failure LED, and Locate LED associated with the specified devices.
off
Turns off only the Status LED and Failure LED associated with the specified devices.
ica
,degraded
Visualizes the
In a Critical Array
pattern.rebuild
,rebuild_p
Visualizes the
Rebuild
pattern. This supports both of the rebuild states for compatibility and legacy reasons.ifa
,failed_array
Visualizes the
In a Failed Array
pattern.hotspare
Visualizes the
Hotspare
pattern.pfa
Visualizes the
Predicted Failure Analysis
pattern.failure
,disk_failed
Visualizes the
Failure
pattern.- ses_abort
SES-2 R/R ABORT
ses_rebuild
SES-2 REBUILD/REMAP
ses_ifa
SES-2 IN FAILED ARRAY
ses_ica
SES-2 IN CRITICAL ARRAY
ses_cons_check
SES-2 CONS CHECK
ses_hotspare
SES-2 HOTSPARE
ses_rsvd_dev
SES-2 RSVD DEVICE
ses_ok
SES-2 OK
ses_ident
SES-2 IDENT
ses_rm
SES-2 REMOVE
ses_insert
SES-2 INSERT
ses_missing
SES-2 MISSING
ses_dnr
SES-2 DO NOT REMOVE
ses_active
SES-2 ACTIVE
ses_enable_bb
SES-2 ENABLE BYP B
ses_enable_ba
SES-2 ENABLE BYP A
ses_devoff
SES-2 DEVICE OFF
ses_fault
SES-2 FAULT
When a non-SES-2 pattern is sent to a device in an enclosure, the pattern is automatically translated to the SCSI Enclosure Services (SES) 2 pattern as shown above.
Non-SES-2 Pattern |
SES-2 Pattern |
---|---|
locate |
ses_ident |
locate_off |
ses_ident |
normal |
ses_ok |
off |
ses_ok |
ica |
ses_ica |
degraded |
ses_ica |
rebuild |
ses_rebuild |
rebuild_p |
ses_rebuild |
ifa |
ses_ifa |
failed_array |
ses_ifa |
hotspare |
ses_hotspare |
pfa |
ses_rsvd_dev |
failure |
ses_fault |
disk_failed |
ses_fault |
12.2.2 List of devices #
When you issue the ledctl
command, the LEDs of the
specified devices are set to the specified pattern and all other LEDs are
turned off. The list of devices can be provided in one of two formats:
A list of devices separated by a comma and no spaces
A list in curly braces with devices separated by a space
If you specify multiple patterns in the same command, the device list for each pattern can use the same or different format. For examples that show the two list formats, see Section 12.2.3, “Examples”.
A device is a path to file in the /dev
directory or in
the /sys/block
directory. The path can identify a
block device, an MD software RAID device, or a container device. For a
software RAID device or a container device, the reported LED state is set
for all of the associated block devices.
The LEDs of devices listed in list_of_devices are set to the given pattern pattern_name and all other LEDs are turned off.
12.2.3 Examples #
To locate a single block device:
>
sudo
ledctl locate=/dev/sda
To turn off the Locate LED for a single block device:
>
sudo
ledctl locate_off=/dev/sda
To locate disks of an MD software RAID device and to set a rebuild pattern for two of its block devices at the same time:
>
sudo
ledctl locate=/dev/md127 rebuild={ /sys/block/sd[a-b] }
To turn off the Status LED and Failure LED for the specified devices:
>
sudo
ledctl off={ /dev/sda /dev/sdb }
To locate three block devices, run one of the following commands (both are equivalent):
>
sudo
ledctl locate=/dev/sda,/dev/sdb,/dev/sdc>
sudo
ledctl locate={ /dev/sda /dev/sdb /dev/sdc }
12.3 More information #
See the following resources for details about the LED patterns and monitoring tools: