Updated the docs

plugins/inputs/smart/README.md

@@ -1,41 +1,57 @@
 # Telegraf S.M.A.R.T. plugin
 
 Get metrics using the command line utility `smartctl` for S.M.A.R.T. (Self-Monitoring, Analysis and Reporting Technology) storage devices. SMART is a monitoring system included in computer hard disk drives (HDDs) and solid-state drives (SSDs)[1] that detects and reports on various indicators of drive reliability, with the intent of enabling the anticipation of hardware failures.
-See smartmontools(https://www.smartmontools.org/).
+See smartmontools (https://www.smartmontools.org/).
 
 If no devices are specified, the plugin will scan for SMART devices via the following command:
 
 ```
 smartctl --scan
 ```
 
-On some platforms (e.g. Darwin/macOS) this doesn't return a useful list of devices and you must instead specify which devices to collect metrics from in the configuration file.
-
 Metrics will be reported from the following `smartctl` command:
 
 ```
-smartctl --info --attributes --nocheck=standby --format=brief <device>
+smartctl --info --attributes --health -n <nocheck> --format=brief <device>
+```
+
+This plugin supports _smartmontools_ version 5.41 and above, but v. 5.41 and v. 5.42
+might require setting `nocheck`, see the comment in the sample configuration.
+
+To enable SMART on a storage device run:
+
+```
+smartctl -s on <device>
 ```
 
 ## Measurements
 
-- smart:
+- smart_device:
 
     * Tags:
+      - `capacity`
       - `device`
       - `device_model`
-      - `serial_no`
-      - `capacity`
       - `enabled`
+      - `health`
+      - `serial_no`
+    * Fields:
+      - `exit_status`
+
+- smart_attribute:
+
+    * Tags:
+      - `device`
+      - `fail`
+      - `flags`
       - `id`
       - `name`
-      - `flags`
-      - `fail`
     * Fields:
+      - `exit_status`
+      - `raw_value`
+      - `threshold`
       - `value`
       - `worst`
-      - `threshold`
-      - `raw_value`
 
 ### Flags
 
@@ -52,25 +68,36 @@ The interpretation of the tag `flags` is:
 ```toml
 # Read metrics from storage devices supporting S.M.A.R.T.
 [[inputs.smart]]
-  ## optionally specify the path to the smartctl executable
+  ## Optionally specify the path to the smartctl executable
   # path = "/usr/bin/smartctl"
   #
-  ## optionally specify devices to exclude from reporting.
-  # exclude = [ "/dev/pass6" ]
+  ## Skip checking disks in this power mode. Defaults to
+  ## "standby" to not wake up disks that have stoped rotating.
+  ## See --nockeck in the man pages for smartctl.
+  ## smartctl version 5.41 and 5.42 have faulty detection of
+  ## power mode and might require changing this value to
+  ## "never" depending on your storage device.
+  # nocheck = "standby"
+  #
+  ## Optionally specify devices to exclude from reporting.
+  # excludes = [ "/dev/pass6" ]
   #
-  ## optionally specify devices, if unset all S.M.A.R.T. devices
-  ## will be included
-  # devices = [ "/dev/ada0" ]
+  ## Optionally specify devices and device type, if unset
+  ## a scan (smartctl --scan) for S.M.A.R.T. devices will
+  ## done and all found will be included except for the
+  ## excluded in excludes.
+  # devices = [ "/dev/ada0 -d atacam" ]
 ```
 
+To run `smartctl` with `sudo` create a wrapper script and use `path` in
+the configuration to execute that.
+
 ## Output
 
-When retrieving stats from the local machine (no server specified):
+Example output from an _Apple SSD_:
 ```
-> smart,serial_no=WD-WMC4N0900000,id=1,name=Raw_Read_Error_Rate,flags=POSR-K,fail=-,host=example,device=/dev/ada0,device_model=WDC\ WD30EFRX-68EUZN0,capacity=3000592982016,enabled=Enabled value=200i,worst=200i,threshold=51i,raw_value=0i 1486892929000000000
-> smart,serial_no=WD-WMC4N0900000,device=/dev/ada0,device_model=WDC\ WD30EFRX-68EUZN0,capacity=3000592982016,enabled=Enabled,id=3,name=Spin_Up_Time,flags=POS--K,fail=-,host=example value=181i,worst=180i,threshold=21i,raw_value=5916i 1486892929000000000
-> smart,device_model=WDC\ WD30EFRX-68EUZN0,capacity=3000592982016,enabled=Enabled,name=Start_Stop_Count,flags=-O--CK,fail=-,device=/dev/ada0,serial_no=WD-WMC4N0900000,id=4,host=example value=100i,worst=100i,threshold=0i,raw_value=18i 1486892929000000000
-> smart,enabled=Enabled,device_model=WDC\ WD30EFRX-68EUZN0,id=5,name=Reallocated_Sector_Ct,capacity=3000592982016,device=/dev/ada0,serial_no=WD-WMC4N0900000,flags=PO--CK,fail=-,host=example value=200i,worst=200i,threshold=140i,raw_value=0i 1486892929000000000
-> smart,serial_no=WD-WMC4N0900000,capacity=3000592982016,enabled=Enabled,name=Seek_Error_Rate,host=example,device=/dev/ada0,id=7,flags=-OSR-K,fail=-,device_model=WDC\ WD30EFRX-68EUZN0 value=200i,worst=200i,threshold=0i,raw_value=0i 1486892929000000000
-> smart,flags=-O--CK,device_model=WDC\ WD30EFRX-68EUZN0,capacity=3000592982016,enabled=Enabled,id=9,name=Power_On_Hours,fail=-,host=example,device=/dev/ada0,serial_no=WD-WMC4N0900000 value=65i,worst=65i,threshold=0i,raw_value=25998i 1486892929000000000
+> smart_attribute,device=/dev/rdisk0,id=194,name=Temperature_Celsius,flags=-O---K,fail=-,host=STIZ0039.lan exit_status=0i,value=64i,worst=21i,threshold=0i,raw_value=36i 1487632495000000000
+> smart_attribute,device=/dev/rdisk0,id=197,name=Current_Pending_Sector,flags=-O---K,fail=-,host=STIZ0039.lan exit_status=0i,value=100i,worst=100i,threshold=0i,raw_value=0i 1487632495000000000
+> smart_attribute,device=/dev/rdisk0,id=199,name=UDMA_CRC_Error_Count,flags=-O-RC-,fail=-,host=STIZ0039.lan exit_status=0i,value=200i,worst=200i,threshold=0i,raw_value=0i 1487632495000000000
+> smart_device,device_model=APPLE\ SSD\ SM256E,serial_no=S0X5NZBC422720,capacity=251000193024,enabled=Enabled,health=PASSED,host=STIZ0039.lan,device=/dev/rdisk0 exit_status=0i 1487632495000000000
 ```