I’m spinning this new topic off of a comment here by @honeybadger
SCALE CE 25.04.2.6 but I don’t think that matters.
The SMART controversy has brought up a new topic of interest - background media scanning. If the drives are autonomously constantly doing read tests in the background across every LBA, then there’s very little difference between that feature (BMS) and SMART long tests.
Recently I had a disk fail so I took this as an opportunity to do an experiment after I received the new warm spare (RIP wallet).
Normally (as my system is for my personal/homelab use) the system powers off/reboots once daily and has a schedule of SMART tests. To prep for this experiment, I disabled the cron job for powering off the system daily and I excluded the new disk from the SMART test schedules (except for the one SMART short test it ran, as I simply forgot).
Below is the smartctl -x output:
# smartctl -x /dev/sdc
smartctl 7.4 2023-08-01 r5530 [x86_64-linux-6.12.15-production+truenas] (local build)
Copyright (C) 2002-23, Bruce Allen, Christian Franke, www.smartmontools.org
=== START OF INFORMATION SECTION ===
Model Family: Western Digital Blue (CMR)
Device Model: WDC WD80EAAZ-00BXBB0
Serial Number: REDACTED
LU WWN Device Id: 5 0014ee 2c173e13a
Firmware Version: 01.01A01
User Capacity: 8,001,563,222,016 bytes [8.00 TB]
Sector Sizes: 512 bytes logical, 4096 bytes physical
Rotation Rate: 5640 rpm
Form Factor: 3.5 inches
Device is: In smartctl database 7.3/6061
ATA Version is: ACS-3 T13/2161-D revision 5
SATA Version is: SATA 3.1, 6.0 Gb/s (current: 3.0 Gb/s)
Local Time is: Sat Mar 7 09:28:57 2026 CST
SMART support is: Available - device has SMART capability.
SMART support is: Enabled
AAM feature is: Unavailable
APM feature is: Unavailable
Rd look-ahead is: Enabled
Write cache is: Enabled
DSN feature is: Unavailable
ATA Security is: Disabled, NOT FROZEN [SEC1]
Wt Cache Reorder: Enabled
Warning! SMART Attribute Thresholds Structure error: invalid SMART checksum.
=== START OF READ SMART DATA SECTION ===
SMART overall-health self-assessment test result: PASSED
General SMART Values:
Offline data collection status: (0x00) Offline data collection activity
was never started.
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: (12884) seconds.
Offline data collection
capabilities: (0x7b) SMART execute Offline immediate.
Auto Offline data collection on/off support.
Suspend Offline collection upon new
command.
Offline surface scan supported.
Self-test supported.
Conveyance Self-test supported.
Selective Self-test supported.
SMART capabilities: (0x0003) Saves SMART data before entering
power-saving mode.
Supports SMART auto save timer.
Error logging capability: (0x01) Error logging supported.
General Purpose Logging supported.
Short self-test routine
recommended polling time: ( 2) minutes.
Extended self-test routine
recommended polling time: ( 804) minutes.
Conveyance self-test routine
recommended polling time: ( 5) minutes.
SCT capabilities: (0x0031) SCT Status supported.
SCT Feature Control supported.
SCT Data Table supported.
SMART Attributes Data Structure revision number: 16
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME FLAGS VALUE WORST THRESH FAIL RAW_VALUE
1 Raw_Read_Error_Rate POSR-K 100 253 051 - 0
3 Spin_Up_Time POS--K 100 253 021 - 0
4 Start_Stop_Count -O--CK 100 100 000 - 1
5 Reallocated_Sector_Ct PO--CK 200 200 140 - 0
7 Seek_Error_Rate -OSR-K 200 200 000 - 0
9 Power_On_Hours -O--CK 100 100 000 - 204
10 Spin_Retry_Count -O--CK 100 253 000 - 0
11 Calibration_Retry_Count -O--CK 100 253 000 - 0
12 Power_Cycle_Count -O--CK 100 100 000 - 1
192 Power-Off_Retract_Count -O--CK 200 200 000 - 0
193 Load_Cycle_Count -O--CK 200 200 000 - 7
194 Temperature_Celsius -O---K 124 117 000 - 28
196 Reallocated_Event_Count -O--CK 200 200 000 - 0
197 Current_Pending_Sector -O--CK 200 200 000 - 0
198 Offline_Uncorrectable ----CK 100 253 000 - 0
199 UDMA_CRC_Error_Count -O--CK 200 200 000 - 0
200 Multi_Zone_Error_Rate ---R-- 200 200 000 - 0
||||||_ K auto-keep
|||||__ C event count
||||___ R error rate
|||____ S speed/performance
||_____ O updated online
|______ P prefailure warning
General Purpose Log Directory Version 1
SMART Log Directory Version 1 [multi-sector log support]
Address Access R/W Size Description
0x00 GPL,SL R/O 1 Log Directory
0x01 SL R/O 1 Summary SMART error log
0x02 SL R/O 5 Comprehensive SMART error log
0x03 GPL R/O 6 Ext. Comprehensive SMART error log
0x04 GPL R/O 256 Device Statistics log
0x04 SL R/O 255 Device Statistics log
0x06 SL R/O 1 SMART self-test log
0x07 GPL R/O 1 Extended self-test log
0x09 SL R/W 1 Selective self-test log
0x10 GPL R/O 1 NCQ Command Error log
0x11 GPL R/O 1 SATA Phy Event Counters log
0x24 GPL R/O 310 Current Device Internal Status Data log
0x30 GPL,SL R/O 9 IDENTIFY DEVICE data log
0x80-0x9f GPL,SL R/W 16 Host vendor specific log
0xa0-0xa1 GPL,SL VS 16 Device vendor specific log
0xa3-0xa7 GPL,SL VS 16 Device vendor specific log
0xa8-0xb6 GPL,SL VS 1 Device vendor specific log
0xb7 GPL,SL VS 80 Device vendor specific log
0xbd GPL,SL VS 1 Device vendor specific log
0xc0 GPL,SL VS 1 Device vendor specific log
0xc1 GPL VS 93 Device vendor specific log
0xe0 GPL,SL R/W 1 SCT Command/Status
0xe1 GPL,SL R/W 1 SCT Data Transfer
SMART Extended Comprehensive Error Log Version: 1 (6 sectors)
No Errors Logged
SMART Extended Self-test Log Version: 1 (1 sectors)
Num Test_Description Status Remaining LifeTime(hours) LBA_of_first_error
# 1 Short offline Completed without error 00% 35 -
# 2 Extended offline Completed without error 00% 14 -
# 3 Conveyance offline Completed without error 00% 0 -
SMART Selective self-test log data structure revision number 1
SPAN MIN_LBA MAX_LBA CURRENT_TEST_STATUS
1 0 0 Not_testing
2 0 0 Not_testing
3 0 0 Not_testing
4 0 0 Not_testing
5 0 0 Not_testing
Selective self-test flags (0x0):
After scanning selected spans, do NOT read-scan remainder of disk.
If Selective self-test is pending on power-up, resume after 0 minute delay.
SCT Status Version: 3
SCT Version (vendor specific): 258 (0x0102)
Device State: Active (0)
Current Temperature: 28 Celsius
Power Cycle Min/Max Temperature: 23/31 Celsius
Lifetime Min/Max Temperature: 23/31 Celsius
Under/Over Temperature Limit Count: 0/0
Vendor specific:
01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
SCT Temperature History Version: 2
Temperature Sampling Period: 1 minute
Temperature Logging Interval: 1 minute
Min/Max recommended Temperature: 0/60 Celsius
Min/Max Temperature Limit: -41/85 Celsius
Temperature History Size (Index): 478 (323)
Index Estimated Time Temperature Celsius
324 2026-03-07 01:31 27 ********
... ..( 42 skipped). .. ********
367 2026-03-07 02:14 27 ********
368 2026-03-07 02:15 28 *********
369 2026-03-07 02:16 28 *********
370 2026-03-07 02:17 27 ********
... ..( 62 skipped). .. ********
433 2026-03-07 03:20 27 ********
434 2026-03-07 03:21 28 *********
... ..( 14 skipped). .. *********
449 2026-03-07 03:36 28 *********
450 2026-03-07 03:37 27 ********
... ..(290 skipped). .. ********
263 2026-03-07 08:28 27 ********
264 2026-03-07 08:29 28 *********
... ..( 58 skipped). .. *********
323 2026-03-07 09:28 28 *********
SCT Error Recovery Control command not supported
Device Statistics (GP Log 0x04)
Page Offset Size Value Flags Description
0x01 ===== = = === == General Statistics (rev 3) ==
0x01 0x008 4 1 --- Lifetime Power-On Resets
0x01 0x010 4 204 --- Power-on Hours
0x01 0x018 6 0 --- Logical Sectors Written
0x01 0x020 6 0 --- Number of Write Commands
0x01 0x028 6 32696 --- Logical Sectors Read
0x01 0x030 6 183 --- Number of Read Commands
0x01 0x038 6 734400000 --- Date and Time TimeStamp
0x02 ===== = = === == Free-Fall Statistics (rev 1) ==
0x02 0x010 4 0 --- Overlimit Shock Events
0x03 ===== = = === == Rotating Media Statistics (rev 1) ==
0x03 0x008 4 204 --- Spindle Motor Power-on Hours
0x03 0x010 4 13 --- Head Flying Hours
0x03 0x018 4 7 --- Head Load Events
0x03 0x020 4 0 --- Number of Reallocated Logical Sectors
0x03 0x028 4 0 --- Read Recovery Attempts
0x03 0x030 4 0 --- Number of Mechanical Start Failures
0x03 0x038 4 0 --- Number of Realloc. Candidate Logical Sectors
0x03 0x040 4 0 --- Number of High Priority Unload Events
0x04 ===== = = === == General Errors Statistics (rev 1) ==
0x04 0x008 4 0 --- Number of Reported Uncorrectable Errors
0x04 0x010 4 0 --- Resets Between Cmd Acceptance and Completion
0x05 ===== = = === == Temperature Statistics (rev 1) ==
0x05 0x008 1 28 --- Current Temperature
0x05 0x010 1 27 --- Average Short Term Temperature
0x05 0x018 1 - --- Average Long Term Temperature
0x05 0x020 1 31 --- Highest Temperature
0x05 0x028 1 25 --- Lowest Temperature
0x05 0x030 1 28 --- Highest Average Short Term Temperature
0x05 0x038 1 25 --- Lowest Average Short Term Temperature
0x05 0x040 1 - --- Highest Average Long Term Temperature
0x05 0x048 1 - --- Lowest Average Long Term Temperature
0x05 0x050 4 0 --- Time in Over-Temperature
0x05 0x058 1 60 --- Specified Maximum Operating Temperature
0x05 0x060 4 0 --- Time in Under-Temperature
0x05 0x068 1 0 --- Specified Minimum Operating Temperature
0x06 ===== = = === == Transport Statistics (rev 1) ==
0x06 0x008 4 2 --- Number of Hardware Resets
0x06 0x010 4 1 --- Number of ASR Events
0x06 0x018 4 0 --- Number of Interface CRC Errors
0xff ===== = = === == Vendor Specific Statistics (rev 1) ==
0xff 0x008 7 0 --- Vendor Specific
0xff 0x010 7 0 --- Vendor Specific
0xff 0x018 7 0 --- Vendor Specific
|||_ C monitored condition met
||__ D supports DSN
|___ N normalized value
Pending Defects log (GP Log 0x0c) not supported
SATA Phy Event Counters (GP Log 0x11)
ID Size Value Description
0x0001 2 0 Command failed due to ICRC error
0x0002 2 0 R_ERR response for data FIS
0x0003 2 0 R_ERR response for device-to-host data FIS
0x0004 2 0 R_ERR response for host-to-device data FIS
0x0005 2 0 R_ERR response for non-data FIS
0x0006 2 0 R_ERR response for device-to-host non-data FIS
0x0007 2 0 R_ERR response for host-to-device non-data FIS
0x0008 2 0 Device-to-host non-data FIS retries
0x0009 2 1 Transition from drive PhyRdy to drive PhyNRdy
0x000a 2 2 Device-to-host register FISes sent due to a COMRESET
0x000b 2 0 CRC errors within host-to-device FIS
0x000d 2 0 Non-CRC errors within host-to-device FIS
0x000f 2 0 R_ERR response for host-to-device data FIS, CRC
0x0012 2 0 R_ERR response for host-to-device non-data FIS, CRC
0x8000 4 736370 Vendor specific
#
My noob analysis is pretty simple:
- Drive’s been running for 8-ish days (that’s about right, I received and installed it into the system on Thu 2026-02-26).
- No issues on the drive.
- The first few SMART tests (long + convayence by me, short by test schedule) all came back clean.
- No evidence of a BMS feature present.
Honeybadger also notes the sdparm command. I’ve never used this command before so I don’t really know what I’m doing, but here’s the output of sdparm --all :
# sdparm --all /dev/sdc
/dev/sdc: ATA WDC WD80EAAZ-00B 1A01
Read write error recovery mode page:
AWRE 1 [cha: n, def: 1]
ARRE 0 [cha: n, def: 0]
TB 0 [cha: n, def: 0]
RC 0 [cha: n, def: 0]
EER 0 [cha: n, def: 0]
PER 0 [cha: n, def: 0]
DTE 0 [cha: n, def: 0]
DCR 0 [cha: n, def: 0]
RRC 0 [cha: n, def: 0]
COR_S 0 [cha: n, def: 0]
HOC 0 [cha: n, def: 0]
DSOC 0 [cha: n, def: 0]
LBPERE 0 [cha: n, def: 0]
MWR 0 [cha: n, def: 0]
WRC 0 [cha: n, def: 0]
RTL 0 [cha: n, def: 0]
Caching (SBC) mode page:
IC 0 [cha: n, def: 0]
ABPF 0 [cha: n, def: 0]
CAP 0 [cha: n, def: 0]
DISC 0 [cha: n, def: 0]
SIZE 0 [cha: n, def: 0]
WCE 1 [cha: y, def: 1]
MF 0 [cha: n, def: 0]
RCD 0 [cha: n, def: 0]
DRRP 0 [cha: n, def: 0]
WRP 0 [cha: n, def: 0]
DPTL 0 [cha: n, def: 0]
MIPF 0 [cha: n, def: 0]
MAPF 0 [cha: n, def: 0]
MAPFC 0 [cha: n, def: 0]
FSW 0 [cha: n, def: 0]
LBCSS 0 [cha: n, def: 0]
DRA 0 [cha: n, def: 0]
SYNC_PROG 0 [cha: n, def: 0]
NV_DIS 0 [cha: n, def: 0]
NCS 0 [cha: n, def: 0]
CSS 0 [cha: n, def: 0]
Control mode page:
TST 0 [cha: n, def: 0]
TMF_ONLY 0 [cha: n, def: 0]
DPICZ 0 [cha: n, def: 0]
D_SENSE 0 [cha: y, def: 0]
GLTSD 1 [cha: n, def: 1]
RLEC 0 [cha: n, def: 0]
QAM 0 [cha: n, def: 0]
NUAR 0 [cha: n, def: 0]
QERR 0 [cha: n, def: 0]
VS_CTL 0 [cha: n, def: 0]
RAC 0 [cha: n, def: 0]
UA_INTLCK 0 [cha: n, def: 0]
SWP 0 [cha: n, def: 0]
ATO 0 [cha: n, def: 0]
TAS 0 [cha: n, def: 0]
ATMPE 0 [cha: n, def: 0]
RWWP 0 [cha: n, def: 0]
SBLP 0 [cha: n, def: 0]
AUTOLOAD 0 [cha: n, def: 0]
BTP -1 [cha: n, def: -1]
ESTCT 30 [cha: n, def: 30]
I don’t see anything in there for BMS, but I’m happy to try out other commands if I’m given some fishing tips.
Is my drive running background media scans (BMS)? How do I find out? How often is BMS completing/running if it’s enabled?
