Smartmontools

This article refers to Smartmontools. You can install it by

opkg update
opkg install smartmontools

To save flash space there is no drivedb included in the OpenWRT package of smartmontools. The automatic update of drive.db described here is missing as well. In case you can affort/waste ~215kB (12-April-2020) you can download the current database from GIT Drivedb.h. Transfer it via SCP or WinSCP and place it at

mkdir /usr/share/smartmontools
mv drivedb.h /usr/share/smartmontools/drivedb.h

It allows you to monitor the health of an external storage device. This example assumes an SSD mounted at /dev/sda

smartctl -a /dev/sda
 
smartctl 7.0 2018-12-30 r4883 [armv5tel-linux-4.14.162] (localbuild)
Copyright (C) 2002-18, Bruce Allen, Christian Franke, www.smartmontools.org
 
=== START OF INFORMATION SECTION ===
Model Family:     Marvell based SanDisk SSDs
Device Model:     SanDisk SSD PLUS 240GB
Serial Number:    1944AA800xxx
LU WWN Device Id: 5 001b44 8b18d5803
Firmware Version: UF2204RL
User Capacity:    240,057,409,536 bytes [240 GB]
Sector Size:      512 bytes logical/physical
Rotation Rate:    Solid State Device
Form Factor:      2.5 inches
Device is:        In smartctl database [for details use: -P show]
ATA Version is:   ACS-3, ACS-2 T13/2015-D revision 3
SATA Version is:  SATA 3.2, 6.0 Gb/s (current: 3.0 Gb/s)
Local Time is:    Mon Apr 13 09:28:31 2020 CEST
SMART support is: Available - device has SMART capability.
SMART support is: Enabled
...
SMART Attributes Data Structure revision number: 1
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME          FLAG     VALUE WORST THRESH TYPE      UPDATED  WHEN_FAILED RAW_VALUE
  5 Reallocated_Sector_Ct   0x0032   100   100   000    Old_age   Always       -       0
  9 Power_On_Hours          0x0032   100   100   000    Old_age   Always       -       215
 12 Power_Cycle_Count       0x0032   100   100   000    Old_age   Always       -       27
165 Total_Write/Erase_Count 0x0032   100   100   000    Old_age   Always       -       34
166 Min_W/E_Cycle           0x0032   100   100   ---    Old_age   Always       -       1
167 Min_Bad_Block/Die       0x0032   100   100   ---    Old_age   Always       -       10
168 Maximum_Erase_Cycle     0x0032   100   100   ---    Old_age   Always       -       3
169 Total_Bad_Block         0x0032   100   100   ---    Old_age   Always       -       106
170 Unknown_Attribute       0x0032   100   100   ---    Old_age   Always       -       0
171 Program_Fail_Count      0x0032   100   100   000    Old_age   Always       -       0
172 Erase_Fail_Count        0x0032   100   100   000    Old_age   Always       -       0
173 Avg_Write/Erase_Count   0x0032   100   100   000    Old_age   Always       -       1
174 Unexpect_Power_Loss_Ct  0x0032   100   100   000    Old_age   Always       -       0
184 End-to-End_Error        0x0032   100   100   ---    Old_age   Always       -       0
187 Reported_Uncorrect      0x0032   100   100   000    Old_age   Always       -       0
188 Command_Timeout         0x0032   100   100   ---    Old_age   Always       -       0
194 Temperature_Celsius     0x0022   063   042   000    Old_age   Always       -       37 (Min/Max 15/42)
199 SATA_CRC_Error          0x0032   100   100   ---    Old_age   Always       -       0
230 Perc_Write/Erase_Count  0x0032   100   100   000    Old_age   Always       -       9 20 9
232 Perc_Avail_Resrvd_Space 0x0033   100   100   005    Pre-fail  Always       -       100
233 Total_NAND_Writes_GiB   0x0032   100   100   ---    Old_age   Always       -       136
234 Perc_Write/Erase_Ct_BC  0x0032   100   100   000    Old_age   Always       -       274
241 Total_Writes_GiB        0x0030   100   100   000    Old_age   Offline      -       131
242 Total_Reads_GiB         0x0030   100   100   000    Old_age   Offline      -       190
244 Thermal_Throttle        0x0032   000   100   ---    Old_age   Always       -       0