SMART Attribute Data Structure error - how to repair?

I've got here three 4 TB HGST HUS724040ALA640 drives. They are mounted
in ICY Box external cases, connected via e-SATA, LUKS-encrypted. They
are used once a week for offline backups and perform fine for years now.

Just today I've noticed that all three of them seem to have invalid
SMART data like below. I'm quite sure that they were normally readable
at beginning.

What might have happened? Surely SMART data is not encrypted by LUKS?
Is there a way to repair/rewrite the SMART data so that they at least
start over fresh?


$ sudo smartctl -iA /dev/sdg

smartctl 6.5 2016-01-24 r4214 [x86_64-linux-3.16.0-4-amd64] (local build)
Copyright (C) 2002-16, Bruce Allen, Christian Franke, www.smartmontools.org

=== START OF INFORMATION SECTION ===
Model Family:     Hitachi/HGST Ultrastar 7K4000
Device Model:     HGST HUS724040ALA640
Serial Number:    PN2331PAH3ZBRT
LU WWN Device Id: 5 000cca 22bcfe6a7
Firmware Version: MFAOAA70
User Capacity:    4.000.787.030.016 bytes [4,00 TB]
Sector Size:      512 bytes logical/physical
Rotation Rate:    7200 rpm
Form Factor:      3.5 inches
Device is:        In smartctl database [for details use: -P show]
ATA Version is:   ATA8-ACS T13/1699-D revision 4
SATA Version is:  SATA 3.0, 6.0 Gb/s (current: 3.0 Gb/s)
Local Time is:    Mon Aug 29 14:01:14 2016 CEST
SMART support is: Available - device has SMART capability.
SMART support is: Enabled

Warning! SMART Attribute Data Structure error: invalid SMART checksum.
Read SMART Thresholds failed: scsi error aborted command

=== START OF READ SMART DATA SECTION ===
SMART Attributes Data Structure revision number: 1114
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME          FLAG     VALUE WORST THRESH TYPE
UPDATED  WHEN_FAILED RAW_VALUE
255 Unknown_Attribute       0x373f   200   016   ---    Pre-fail  Always
      -       69269232549888
 78 Unknown_Attribute       0x3350   050   049   ---    Old_age
Offline      -       72877865976115
 84 Unknown_Attribute       0x0652   123   039   ---    Old_age   Always
      -       87193305495667
 65 Unknown_Attribute       0x3041   055   071   ---    Pre-fail
Offline      -       91398117479496
 50 Unknown_Attribute       0x3037   052   048   ---    Pre-fail  Always
      -       53056641256500
 32 Unknown_Attribute       0x2020   032   032   ---    Old_age
Offline      -       35322350018592
 32 Unknown_Attribute       0x2020   032   032   ---    Old_age
Offline      -       550026354720
 16 Unknown_Attribute       0x3f00   000   016   ---    Old_age
Offline      -       280379760114684
255 Unknown_Attribute       0x000f   000   007   ---    Pre-fail  Always
      -       131943408599808
120 Unknown_Attribute       0x7800   000   000   ---    Old_age
Offline      -       0
 64 Unknown_Attribute       0xfc00   001   041   ---    Old_age
Offline      -       56613733165824
105 Unknown_Attribute       0x4174   188   099   ---    Old_age
Offline      -       4282416967
254 Free_Fall_Sensor        0xfe00   255   000   ---    Old_age
Offline      -       222101483028480
249 Unknown_Attribute       0x1000   039   000   ---    Old_age
Offline      -       2000393515008
162 Unknown_Attribute       0xcfcc   043   167   ---    Old_age
Offline      -       230
241 Total_LBAs_Written      0x200d   250   001   ---    Pre-fail
Offline      -       7713832566784
  4 Start_Stop_Count        0x0607   006   004   ---    Pre-fail  Always
      -       6627185329158
  6 Read_Channel_Margin     0x3700   065   065   ---    Old_age
Offline      -       103246987330
185 Unknown_Attribute       0xff5d   255   000   ---    Pre-fail
Offline      -       128
255 Unknown_Attribute       0xbf00   207   000   ---    Old_age
Offline      -       0



-- 
Hans


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