SMART tests and "offline data collection"

[saurav]

I have a bunch of questions about the SMAT service and SMART tests in general:

1. Does the SMART service actually run any tests every 30 minutes, or does it only check the SMART logs (like with "smartctl -a" or "smartctl -x")? I have short tests scheduled for everyday, but if SMART service is anyway doing it every 30 minutes, then may be I just need to schedule for long tests and not short ones?

2. Some of the SMART attributes are updated only during "automatic offline testing", like these two

198 Offline_Uncorrectable 0x0030 100 253 000 Old_age Offline - 0
200 Multi_Zone_Error_Rate 0x0008 200 200 000 Old_age Offline - 0

However, "smartctl -a" on one of the disks says:

Offline data collection status: (0x00)
Offline data collection activity was never started.
Auto Offline Data Collection: Disabled.

So, should I turn it on with "smartctl --offlineauto=on"? But then the smartctl manpage says

Note that the SMART automatic offline test command is listed as "Obsolete" in every version of the ATA and ATA/ATAPI Specifications. It was originally part of the SFF-8035i Revision 2.0 specification, but was never part of any ATA specification. However it is implemented and used by many vendors. [Good documentation can be found in IBM's Official Published Disk Specifications. For example the IBM Travelstar 40GNX Hard Disk Drive Specifications (Revision 1.1, 22 April 2002, Publication # 1541, Document S07N-7715-02) page 164. You can also read the SFF-8035i Specification -- see REFERENCES below.] You can tell if automatic offline testing is supported by seeing if this command enables and disables it, as indicated by the 'Auto Offline Data Collection' part of the SMART capabilities report (displayed with '-c').

So what is the right thing to do here? Should I enable it, or just let it be?

Thanks,
Saurav.

 

[Ericloewe]

SMART queries the drive every 30 minutes. This typically involves reading the current SMART data of the disks, so spin up will happen unless specifically told not to.

Don't worry about those values, they'll get updated by the drive as soon as you have to start worrying about them (that is, when they actually increase).