Configuring S.M.A.R.T. Tests

How to configure S.M.A.R.T. tests for installed disks.

  4 minute read

S.M.A.R.T. (Self-Monitoring, Analysis and Reporting Technology) is an industry standard for disk monitoring and testing. Disks can be monitored for problems, with several different kinds of self-tests available. TrueNAS can adjust when and how alerts for SMART are issued. When S.M.A.R.T. monitoring reports an issue, it is recommended to replace that disk. Most modern ATA, IDE, and SCSI-3 hard drives support S.M.A.R.T. Refer to your respective drive documentation for confirmation.

S.M.A.R.T. tests are run on a disk. Running tests can reduce drive performance, so it is recommended to schedule tests when the system is in a low-usage state. Avoid scheduling disk-intensive tests at the same time! For example, S.M.A.R.T. tests should not be scheduled on the same day as a disk scrub or resilver.

To disable all S.M.A.R.T. testing for a disk, go to Storage > Disks, select a disk, and click EDIT DISK(S). Unset Enable S.M.A.R.T..

Manual S.M.A.R.T. Test

To quickly test a disk for errors, go to Storage > Disks and select the disks to be tested. After selecting the desired disks, click MANUAL TEST.



Next, select the test Type. Each test type can be slightly different based on the drive connection (ATA or SCSI):

  • Long - [ATA] runs SMART Extended Self Test. This will scan the entire disk surface and can take many hours on large-volume disks.
  • Long - [SCSI] runs the “Background long” self-test.
  • Short - [ATA] runs SMART Short Self Test (usually under ten minutes). These are basic disk tests that vary by manufacturer.
  • Short - [SCSI] runs the “Background short” self-test.
  • Conveyance - [ATA only] runs a SMART Conveyance Self Test (minutes). This self-test routine is intended to identify damage incurred during transporting of the device. This self-test routine should take on the order of minutes to complete.
  • Offline - [ATA] runs SMART Immediate Offline Test. The effects of this test are visible only in that it updates the SMART Attribute values, and if errors are found they will appear in the SMART error log.
  • Offline - [SCSI] runs the default self test in foreground. No entry is placed in the self test log.

For more information, refer to smartctl(8).

Click START to begin the test. Depending on the chosen test type, the test can take some time to complete.

Test results can be viewed by expanding a Storage > Disks entry and clicking S.M.A.R.T. TEST RESULTS. To find test results from the shell, use smartctl and the name of the drive: smartctl -l selftest /dev/ada0.

Automatic S.M.A.R.T. Tests

To schedule recurring S.M.A.R.T. tests, go to Tasks > S.M.A.R.T. Tests and click ADD.



Setting All Disks will include every disk that has S.M.A.R.T. enabled in the test. To check if a disk has S.M.A.R.T. Enabled, go to Storage > Disks and expand a disk entry. Enable S.M.A.R.T. shows true or false.

To specify which disks to test, leave All Disks unset and make selections from the Disks drop down.

Select a test type from the Type dropdown. Test types are the same as a manual test.

Finally, select a schedule for the S.M.A.R.T. test. If a custom schedule is desired, select Custom and fill out the custom scheduler to meet your needs.

Saved schedules appear in the Tasks > S.M.A.R.T. Tests list. To verify the schedule is saved, you can open the shell and enter smartd -q showtests.

Service Options

The S.M.A.R.T. service must be turned on for automatic S.M.A.R.T. tests to function.

It is recommended to disable the S.M.A.R.T. service when disks are controlled by a RAID controller. The controller will monitor S.M.A.R.T. separately and mark disks as a Predictive Failure on a test failure.

To turn the S.M.A.R.T. service on, go to Services and click the slider for S.M.A.R.T.. If you wish to turn the service on automatically when the TrueNAS system is turned on, set Start Automatically.

The S.M.A.R.T. service settings can be configured by clicking   (Configure).



Check Interval is the amount of time, in minutes, the smartd service checks for S.M.A.R.T. tests to run on the system. smartd wakes up at the configured interval and checks the times configured in Tasks > S.M.A.R.T. Tests to see if a test must begin. For example, if a SMART test is scheduled to run every 15 minutes but the Check Interval is 30 minutes, then the SMART test only runs every 30 minutes when the smartd service activates.

Enter a number of degrees in Celsius for the Difference. S.M.A.R.T. reports if the temperature of a drive has changed by the number of degrees Celsius specified since the last report.

Enter a threshold temperature in Celsius for Informational. S.M.A.R.T. will message with a log level of LOG_INFO if the temperature is higher than the threshold specified.

Enter a threshold temperature in Celsius for Critical. S.M.A.R.T. will message with a log level of LOG_CRIT if the temperature is higher than the threshold.

Don’t forget to click SAVE after changing any settings.


Last modified January 12, 2021: Update smart.md (d875e027)