# apt-get install smartmontools

# smartctl -i /dev/sda

=== START OF INFORMATION SECTION ===
Model Family:     Western Digital Red
Device Model:     WDC WDXXXXXX-XXXXXXX
LU WWN Device Id: 5 0014ee 20c672def
Firmware Version: 82.00A82
User Capacity:    1,000,204,886,016 bytes [1.00 TB]
Sector Sizes:     512 bytes logical, 4096 bytes physical
Rotation Rate:    5400 rpm
Device is:        In smartctl database [for details use: -P show]
ATA Version is:   ACS-2 (minor revision not indicated)
SATA Version is:  SATA 3.0, 6.0 Gb/s (current: 3.0 Gb/s)
Local Time is:    Thu Sep 24 18:13:19 2020 CEST
SMART support is: Available - device has SMART capability.
SMART support is: Disabled

If smart is disable we can switch on with:

# smartctl -s on /dev/sda

smartctl 6.6 2017-11-05 r4594 [armv6l-linux-5.4.51+] (local build)
Copyright (C) 2002-17, Bruce Allen, Christian Franke, www.smartmontools.org

=== START OF ENABLE/DISABLE COMMANDS SECTION ===
SMART Enabled.

Get information about the device

# smartctl -a /dev/sda

...
SMART Attributes Data Structure revision number: 16
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME          FLAG     VALUE WORST THRESH TYPE      UPDATED  WHEN_FAILED RAW_VALUE
  1 Raw_Read_Error_Rate     0x002f   200   200   051    Pre-fail  Always       -       0
  3 Spin_Up_Time            0x0027   135   125   021    Pre-fail  Always       -       4216
  4 Start_Stop_Count        0x0032   100   100   000    Old_age   Always       -       941
  5 Reallocated_Sector_Ct   0x0033   200   200   140    Pre-fail  Always       -       0
  7 Seek_Error_Rate         0x002e   200   200   000    Old_age   Always       -       0
  9 Power_On_Hours          0x0032   085   085   000    Old_age   Always       -       11285
 10 Spin_Retry_Count        0x0032   100   100   000    Old_age   Always       -       0
 11 Calibration_Retry_Count 0x0032   100   100   000    Old_age   Always       -       0
 12 Power_Cycle_Count       0x0032   100   100   000    Old_age   Always       -       446
192 Power-Off_Retract_Count 0x0032   200   200   000    Old_age   Always       -       108
193 Load_Cycle_Count        0x0032   199   199   000    Old_age   Always       -       4258
194 Temperature_Celsius     0x0022   111   099   000    Old_age   Always       -       32
196 Reallocated_Event_Count 0x0032   200   200   000    Old_age   Always       -       0
197 Current_Pending_Sector  0x0032   200   200   000    Old_age   Always       -       0
198 Offline_Uncorrectable   0x0030   100   253   000    Old_age   Offline      -       0
199 UDMA_CRC_Error_Count    0x0032   200   200   000    Old_age   Always       -       0
200 Multi_Zone_Error_Rate   0x0008   200   200   000    Old_age   Offline      -       0
...

Reallocated_Sector_Ct and Current_Pending_Sector must be 0 (Zero) otherwise there is something wrong!