SMART - Understanding Offline Data Collection

manpreet Best Answer 2 years ago

I have two Kingston A400 120GB SSD as cache in a Synology NAS, which don't seem to support automatic offline data collection.

# smartctl -d sat -c /dev/sdc | grep -i "Auto Offline data collection" 
Auto Offline Data Collection: Disabled.  
No Auto Offline data collection support.
# smartctl -d sat -o on /dev/sdc
SMART Automatic Timers not supported
SMART Enable Automatic Offline failed: scsi error aborted command

Yet when I check the attributes marked as "Offline", the RAW_VALUE one of them keeps changing (specifically 246 Total_Erase_Count), even if I dont run the manual offline data collection or self-tests in between. I checked if smartd was running just in case, but it isn't. Same thing happens with the other identical SSD.

Questions:

1. What exactly does the offline data collection update? Does it just update the VALUE/WORST/THRESH columns in the attribute table?
2. Do short or long self-tests update the SMART attribute data?

Output of smartctl -a:

=== START OF INFORMATION SECTION ===
Model Family:     Phison Driven SSDs
Device Model:     KINGSTON SA400S37120G
Serial Number:    [...]
LU WWN Device Id: [...]
Firmware Version: 03070009
User Capacity:    120,034,123,776 bytes [120 GB]
Sector Size:      512 bytes logical/physical
Rotation Rate:    Solid State Device
Device is:        In smartctl database [for details use: -P show]
ATA Version is:   ACS-3 T13/2161-D revision 4
SATA Version is:  SATA 3.2, 6.0 Gb/s (current: 1.5 Gb/s)
Local Time is:    Fri Apr 12 01:55:30 2019 -03
SMART support is: Available - device has SMART capability.
SMART support is: Enabled

=== START OF READ SMART DATA SECTION ===
SMART overall-health self-assessment test result: PASSED

General SMART Values:
Offline data collection status:  (0x02) Offline data collection activity
                                        was completed without error.
                                        Auto Offline Data Collection: Disabled.
Self-test execution status:      (   0) The previous self-test routine completed
                                        without error or no self-test has ever
                                        been run.
Total time to complete Offline
data collection:                (    0) seconds.
Offline data collection
capabilities:                    (0x35) SMART execute Offline immediate.
                                        No Auto Offline data collection support.
                                        Abort Offline collection upon new
                                        command.
                                        No Offline surface scan supported.
                                        Self-test supported.
                                        Conveyance Self-test supported.
                                        No Selective Self-test supported.
SMART capabilities:            (0x0002) Does not save SMART data before
                                        entering power-saving mode.
                                        Supports SMART auto save timer.
Error logging capability:        (0x00) Error logging NOT supported.
                                        General Purpose Logging supported.
Short self-test routine
recommended polling time:        (   1) minutes.
Extended self-test routine
recommended polling time:        (   1) minutes.
Conveyance self-test routine
recommended polling time:        (   1) minutes.

SMART Attributes Data Structure revision number: 5
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME                                                   FLAG     VALUE WORST THRESH TYPE      UPDATED  WHEN_FAILED RAW_VALUE
  1 Raw_Read_Error_Rate                                              0x0032   100   100   000    Old_age   Always       -       0
  9 Power_On_Hours                                                   0x0032   100   100   000    Old_age   Always       -       710
 12 Power_Cycle_Count                                                0x0032   100   100   000    Old_age   Always       -       5
148 Unknown_Attribute                                                0x0000   100   100   000    Old_age   Offline      -       0
149 Unknown_Attribute                                                0x0000   100   100   000    Old_age   Offline      -       0
167 Unknown_Attribute                                                0x0000   100   100   000    Old_age   Offline      -       0
168 SATA_Phy_Error_Count                                             0x0012   100   100   000    Old_age   Always       -       0
169 Unknown_Attribute                                                0x0000   100   100   000    Old_age   Offline      -       65
170 Bad_Blk_Ct_Erl/Lat                                               0x0000   100   100   010    Old_age   Offline      -       0/78
172 Unknown_Attribute                                                0x0032   100   100   000    Old_age   Always       -       0
173 MaxAvgErase_Ct                                                   0x0000   100   100   000    Old_age   Offline      -       0
181 Program_Fail_Cnt_Total                                           0x0032   100   100   000    Old_age   Always       -       0
182 Erase_Fail_Count_Total                                           0x0000   100   100   000    Old_age   Offline      -       0
187 Reported_Uncorrect                                               0x0032   100   100   000    Old_age   Always       -       0
192 Unsafe_Shutdown_Count                                            0x0012   100   100   000    Old_age   Always       -       1
194 Temperature_Celsius                                              0x0022   024   025   000    Old_age   Always       -       24 (Min/Max 24/25)
196 Not_In_Use                                                       0x0032   100   100   000    Old_age   Always       -       0
199 CRC_Error_Count                                                  0x0032   100   100   000    Old_age   Always       -       0
218 CRC_Error_Count                                                  0x0032   100   100   000    Old_age   Always       -       4
231 SSD_Life_Left                                                    0x0000   100   100   000    Old_age   Offline      -       0
233 Flash_Writes_GiB                                                 0x0032   100   100   000    Old_age   Always       -       396
241 Lifetime_Writes_GiB                                              0x0032   100   100   000    Old_age   Always       -       304
242 Lifetime_Reads_GiB                                               0x0032   100   100   000    Old_age   Always       -       228
244 Average_Erase_Count                                              0x0000   100   100   000    Old_age   Offline      -       2
245 Max_Erase_Count                                                  0x0000   100   100   000    Old_age   Offline      -       10
246 Total_Erase_Count                                                0x0000   100   100   000    Old_age   Offline      -       3827

SMART Error Log not supported

SMART Self-test Log not supported

Selective Self-tests/Logging not supported