SMART Fail: Seek Error Rate

[Circaflex]

Trying to get my head around this one. Had a drive show SMART failure signs in Scanner. Added a new disk to the pool, removed the failing drive and low and behold, after the data was moved over SMART isnt showing signs of failure. Had Scanner perform a full scan on the drive overnight and it came back without any issues. I am always worried when it comes to SMART failures. I couldnt find a reliable Toshiba based diagnostic tool for my drive, but I am both nervous to add this drive back into the pool but also curious about this particular SMART error. I read through forums and everyone seems to have a different opinion on the error.

[Shane]

Basically SMART errors can be divided into "it may fix itself" and "it won't fix itself". Neither is necessarily "replace it ASAP" but it's more probable with the latter.

Seek error rate is with respect to how well the drive is moving the head(s) to the correct position and can change over time due to various factors (vibration, temperature, wear, etc). It is not usually by itself a sign of a failing drive (e.g. a consistently high seek error rate can indicate a defect that can't be compensated for but isn't ultimately preventing the drive from reading and writing data, just slowing it down).

Drives can self-correct to an extent; if a SMART error pops up and then disappears shortly after and doesn't return, the drive's own logic has most likely taken care of it.  E.g. in the case of seek errors, the drive may adjust parameters of the head movements to compensate. Scanner polls SMART frequently by default and thus it can often catch these temporary errors before a drive can finish self-correcting the issue. These temporary errors can also be due to circumstances beyond a drive's control (e.g. occasionally running hot due to high load or insufficient cooling, or something in the chassis is loose and causing vibrations) so it's still useful to know about.

P.S. DrivePool's Scanner balancer plug-in has two tiers of whether to automatically evacuate, warnings (basically SMART has reported something to complain about) and damage (SMART is reporting there's something the drive can't fix or Scanner's own scans are finding damage).

[Christopher (Drashna)]

Also, you can ignore a setting in StableBit Scanner.  Either if the values get worse, it will reflag them, or to permanently ignore them.   Depending on the exact values, you may not want to do that. 

However, IIRC,  seek error rate is one that will change based on various factors.  So it can improve, and go away.  Also, some manufacturers are ... overly aggressive in what is bad.