[OmniOS-discuss] zpool degraded while smart sais disks are OK

[Tobias Oetiker]

Yesterday Richard Elling wrote:

>
> On Mar 21, 2014, at 3:23 PM, Tobias Oetiker <tobi at oetiker.ch> wrote:

[...]
> >
> > it happened over time as you can see from the timestamps in the
> > log. The errors from zfs's point of view were 1 read and about 30 write
> >
> > but according to smart the disks are without flaw
>
> Actually, SMART is pretty dumb. In most cases, it only looks for uncorrectable
> errors that are related to media or heads. For a clue to more permanent errors,
> you will want to look at the read/write error reports for errors that are
> corrected with possible delays. You can also look at the grown defects list.
>
> This behaviour is expected for drives with errors that are not being quickly
> corrected or have firmware bugs (horrors!) and where the disk does not do TLER
> (or its vendor's equivalent)
>  -- richard

the error counters look like this:


Error counter log:
           Errors Corrected by           Total   Correction     Gigabytes    Total
               ECC          rereads/    errors   algorithm      processed    uncorrected
           fast | delayed   rewrites  corrected  invocations   [10^9 bytes]  errors
read:       3494        0         0      3494      44904        530.879           0
write:         0        0         0         0      39111       1793.323           0
verify:        0        0         0         0       8133          0.000           0

the disk vendor is HGST in case anyone has further ideas ... the system has 20 of these disks and the problems occured with
three of them. The system has been running fine for two months previously.

Vendor:               HGST
Product:              HUS724030ALS640
Revision:             A152
User Capacity:        3,000,592,982,016 bytes [3.00 TB]
Logical block size:   512 bytes
Serial number:        P8J20SNV
Device type:          disk
Transport protocol:   SAS

cheers
tobi
>
>

-- 
Tobi Oetiker, OETIKER+PARTNER AG, Aarweg 15 CH-4600 Olten, Switzerland
www.oetiker.ch tobi at oetiker.ch +41 62 775 9902
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