hardware - Does "smartctl -H or -all" run anything against disks or just poll data?

I am setting up Smart monitoring currently and I had a question regarding the command

smartctl -H /dev/sda

=== START OF READ SMART DATA SECTION ===
SMART Health Status: OK

Does this actually run anything against the disk, or does it just poll the logs/data currently available from SmartMonTools.

I understand and am looking into running smartd with short and long tests, but that would be managed by smartd. My script is simple in that it just greps for Health Status OK and fails/passed based on finding the result. It also displays "smartctl -all /dev/sda", and I wondered about that too.

I just want to make sure, because

I Think that both smartctl -H /dev/sda && smartctl -all /dev/sda when run, don't actually do any testing, they just poll avaialable data. Can anybody confirm?

The reason is I poll this data way to often with my network monitoring software (every 15m currently), but if it doesn't effect disks, I will just leave it and use smartd to schedule the actual self-tests which do 100% read/write/test the disks.

Answer

As a fellow user of the tool (not a developer), I would assume they don't run any tests because, looking at the man page:

• -H appears under "SMART READ AND DISPLAY DATA OPTIONS"





• -a, --all appear under "SHOW INFORMATION OPTIONS"




• all the tests are under "SMART RUN/ABORT OFFLINE TEST AND self-test OPTIONS"

If this were not convincing enough, I would also ask on the mailing lists on their homepage.