Re: Couple of questions about Offline data collection [resent in plaintext]

[email protected] wrote:
> Hello.
>
> My questions could be silly and answers could be obvious, but I'll be glad if you point me to the right docs.

See
https://www.smartmontools.org/wiki/Links#ATAATAPIReferences
https://www.smartmontools.org/wiki/Links#TheoriginalSMARTspecification


> What exactly does the Offline data collection? As far as I understood, it's contrary to short and long self-tests, and results are written to "Offline" attributes such as "Offline_uncorrectable".

This was possibly the original idea. What actually happens is hidden in 
firmware and typically not documented by device vendors.


> Long self-test, above all, tries to read and verify every sector of the hard drive. This test can run for 214 minutes on my 2TB Seagate Barracuda 7200.14, but the Offline data collection runs only for 575 seconds.
> Does it mean that Offline data collection is not trying to read/verify every sector, and there could be dozens of unreadable sectors out there, and I'll know about them only after long selftest?

Yes.


> The other question is about Auto Offline data collection: I cannot enable it on my drives:
> ...
> # smartctl -s on -S on -o on /dev/sda
> ...
> # smartctl -c /dev/sda
> === START OF READ SMART DATA SECTION ===
> General SMART Values:
> Offline data collection status:  (0x00) Offline data collection activity
>                                          was never started.
>                                          Auto Offline Data Collection: Disabled.
>
> I've tried to issue the test with '-t offline', and I saw errors in '-l error' log, but the Auto collection cannot be enabled without any reasons.

Then the "SMART ENABLE AUTOMATIC OFF-LINE" ATA command is unsupported by 
the drive firmware (see -o option on smartctl man page).

Regards,
Christian


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