disk errors - what do they really, really mean?


t3

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i did move some 300gb files off the array over night, und when i came back the next day, one of the disks (holding most of them) was offline; there were 7000+ errors printed in the main tab stats, and the syslog shows lots of sector read errors (and a few write errors).

 

ok, disk is dead or dying - might be. but what does it mean for the files that were copied off that particular drive?

 

apparently, the drive did not go offline on the first occurrence of a read error but after ~7000 of them, means some files were definitely read only using parity info, others apparently were not...

so, were they corrected?

by disk mechanisms?

by additional parity reads?

or are they now broken?!?

 

would be good, i guess, if unraid hints users about if they need to be scared about the error count in the gui ;)

 

oh, and btw, i think it would be really, really good to have a simple gui-guided procedure to replace (or remove) failed disks in the most ideal way, reducing risk of data loss to a minimum. since this happens rather seldom, it simply means you are always (again) untrained, but it still touches one of the most important parts of unraid - data safety. so it's always again scaring to read through more or less outdated wiki articles and posts showing 10+ steps to follow, and to decide how to proceed on at this point - and i guess that happens to everybody in such a case...

Edited by t3
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1 hour ago, johnnie.black said:

Post your diagnostics:

 

 

yep, ok, thanks... scratch the first part - i should have read the integrated help, where it is stated that read errors are indeed backed by parity :$

 

 

i'm now going to find my way through the replacement procedure(s)...

Edited by t3
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