smartctl background scan log for SAS drives

[seanacais]

Hi all:

I'm looking at the smartctl background scan log for the following drive:

Code:

# smartctl -a /dev/da2
smartctl 7.0 2018-12-30 r4883 [FreeBSD 11.3-RELEASE-p6 amd64] (local build)
Copyright (C) 2002-18, Bruce Allen, Christian Franke, www.smartmontools.org

=== START OF INFORMATION SECTION ===
Vendor:               HITACHI
Product:              HUS723020ALS640
Revision:             A222
Compliance:           SPC-4
User Capacity:        2,000,398,934,016 bytes [2.00 TB]
Logical block size:   512 bytes
Rotation Rate:        7200 rpm
Form Factor:          3.5 inches
Logical Unit id:      0x5000cca01c461904
Serial number:        YGH7K2TD
Device type:          disk
Transport protocol:   SAS (SPL-3)
Local Time is:        Thu Jun 18 18:45:55 2020 EDT
SMART support is:     Available - device has SMART capability.
SMART support is:     Enabled
Temperature Warning:  Enabled

=== START OF READ SMART DATA SECTION ===
SMART Health Status: OK

Current Drive Temperature:     49 C
Drive Trip Temperature:        85 C

Manufactured in week 17 of year 2012
Specified cycle count over device lifetime:  50000
Accumulated start-stop cycles:  115
Specified load-unload count over device lifetime:  600000
Accumulated load-unload cycles:  69492
Elements in grown defect list: 0

Vendor (Seagate Cache) information
  Blocks sent to initiator = 22625316904108032

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:          0   719404         0    719404   19254638     104694.571           0
write:         0  7588678         0   7588678    3095786      34694.437           0
verify:        0        0         0         0     615073          0.000           0

Non-medium error count:        1

No Self-tests have been logged

# smartctl -l background /dev/da2
Password:
smartctl 7.0 2018-12-30 r4883 [FreeBSD 11.3-RELEASE-p6 amd64] (local build)
Copyright (C) 2002-18, Bruce Allen, Christian Franke, www.smartmontools.org

=== START OF READ SMART DATA SECTION ===
Background scan results log
  Status: waiting until BMS interval timer expires
    Accumulated power on time, hours:minutes 387:14 [23234 minutes]
    Number of background scans performed: 382,  scan progress: 0.00%
    Number of background medium scans performed: 382

   #  when        lba(hex)    [sk,asc,ascq]    reassign_status
   1 58579:53  00000000a8447805  [3,11,0]   Recovered via rewrite in-place
   2 58579:53  00000000a8447804  [3,11,0]   Recovered via rewrite in-place
   3 58579:53  00000000a8447803  [3,11,0]   Recovered via rewrite in-place
   4 58579:53  00000000a8447802  [3,11,0]   Recovered via rewrite in-place
   5 58579:53  00000000a8447801  [3,11,0]   Recovered via rewrite in-place
   6 58579:53  00000000a8447800  [3,11,0]   Recovered via rewrite in-place

I see that several blocks have been reassigned and the grown defect list is still at zero so I'm not too concerned about the drive.

I would like to know when these blocks were reassigned since I recently had a hard UPS fail which crashed the system and I thought the rewrites might be related to that event.

So the "when" column implies that there are over 58,000 hours on the drive. That seems reasonable since that's about 6 years and 7 months of run time and the drive is just over 8 years old.

The "accumulated power on time" is reading just over 387 hours. I acquired this drive in 2017 (no idea how many hours were on it at that time) but it has run continuously since then so I should have at least 20,000 hours on it.

Am I misunderstanding "accumulated power on time"? Is there something that can reset it?

This is not unique to this drive either. I'm seeing the same thing in the entire set of 4 drives.

I feel like I'm missing something here and am seeking understanding.

Thanks,

Kevin