This guide is a set of tips gathered from personal experiences.
Ensure proper understanding and risk when executing any commands from this guide.
Data loss is possible.
The BredOS News service now will report failing or damaged drives that are attached and present S.M.A.R.T data.
If you've been linked to this from BredOS News, head to the following section.
Failures
Assuming hard disk /dev/sda, to view it's S.M.A.R.T data, run:
sudo smartctl -a /dev/sda
This will print out a large report:
[bill88t@prion | ~]> sudo smartctl -a /dev/sda
smartctl 7.5 2025-04-30 r5714 [aarch64-linux-6.1.44-1-sky1] (local build)
Copyright (C) 2002-25, Bruce Allen, Christian Franke, www.smartmontools.org
=== START OF INFORMATION SECTION ===
Model Family: Toshiba 3.5" DT01ACA... Desktop HDD
Device Model: TOSHIBA DT01ACA050
Serial Number: X5NGNE1GS
LU WWN Device Id: 5 000039 fe4d4c15b
Firmware Version: MS1OA750
User Capacity: 500,107,862,016 bytes [500 GB]
Sector Sizes: 512 bytes logical, 4096 bytes physical
Rotation Rate: 7200 rpm
Form Factor: 3.5 inches
Device is: In smartctl database 7.5/5706
ATA Version is: ATA8-ACS T13/1699-D revision 4
SATA Version is: SATA 3.0, 6.0 Gb/s (current: 6.0 Gb/s)
Local Time is: Sun Jun 1 13:03:14 2025 EEST
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: (0x84) Offline data collection activity
was suspended by an interrupting command from host.
Auto Offline Data Collection: Enabled.
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: ( 3498) seconds.
Offline data collection
capabilities: (0x5b) SMART execute Offline immediate.
Auto Offline data collection on/off support.
Suspend Offline collection upon new
command.
Offline surface scan supported.
Self-test supported.
No 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: ( 1) minutes.
Extended self-test routine
recommended polling time: ( 59) minutes.
SCT capabilities: (0x003d) SCT Status supported.
SCT Error Recovery Control 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 FLAG VALUE WORST THRESH TYPE UPDATED WHEN_FAILED RAW_VALUE
1 Raw_Read_Error_Rate 0x000b 100 100 016 Pre-fail Always - 0
2 Throughput_Performance 0x0005 142 142 054 Pre-fail Offline - 71
3 Spin_Up_Time 0x0007 126 126 024 Pre-fail Always - 184 (Average 181)
4 Start_Stop_Count 0x0012 100 100 000 Old_age Always - 117
5 Reallocated_Sector_Ct 0x0033 100 100 005 Pre-fail Always - 0
7 Seek_Error_Rate 0x000b 100 100 067 Pre-fail Always - 0
8 Seek_Time_Performance 0x0005 110 110 020 Pre-fail Offline - 36
9 Power_On_Hours 0x0012 091 091 000 Old_age Always - 65606
10 Spin_Retry_Count 0x0013 100 100 060 Pre-fail Always - 0
12 Power_Cycle_Count 0x0032 100 100 000 Old_age Always - 115
192 Power-Off_Retract_Count 0x0032 100 100 000 Old_age Always - 196
193 Load_Cycle_Count 0x0012 100 100 000 Old_age Always - 196
194 Temperature_Celsius 0x0002 139 139 000 Old_age Always - 43 (Min/Max 19/49)
196 Reallocated_Event_Count 0x0032 100 100 000 Old_age Always - 0
197 Current_Pending_Sector 0x0022 100 100 000 Old_age Always - 0
198 Offline_Uncorrectable 0x0008 100 100 000 Old_age Offline - 0
199 UDMA_CRC_Error_Count 0x000a 200 200 000 Old_age Always - 0
SMART Error Log Version: 1
No Errors Logged
SMART Self-test log structure revision number 1
No self-tests have been logged. [To run self-tests, use: smartctl -t]
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.
The above only provides legacy SMART information - try 'smartctl -x' for more
Out of all of this, the following data are important to look for:
SMART overall-health self-assessment, which should be "PASSED". If any other value is reported, the drive should be replaced with haste.Reallocated_Sector_Ct, the number of relocated sectors, which if more than a single one indicates significant risk of cascading failure.Assuming NVME /dev/nvme0, to view it's S.M.A.R.T data, run:
sudo smartctl -a /dev/nvme0
Assuming the NVME supports S.M.A.R.T, this will print out a small report:
[bill88t@prion | ~]> sudo smartctl -a /dev/nvme0
smartctl 7.5 2025-04-30 r5714 [aarch64-linux-6.1.44-1-sky1] (local build)
Copyright (C) 2002-25, Bruce Allen, Christian Franke, www.smartmontools.org
=== START OF INFORMATION SECTION ===
Model Number: ADATA LEGEND 710
Serial Number: 2O252LASS72J
Firmware Version: VC2SAD01
PCI Vendor/Subsystem ID: 0x1cc1
IEEE OUI Identifier: 0x707c18
Controller ID: 1
NVMe Version: 1.4
Number of Namespaces: 1
Namespace 1 Size/Capacity: 256,060,514,304 [256 GB]
Namespace 1 Formatted LBA Size: 512
Namespace 1 IEEE EUI-64: 707c18 0c83eec2e9
Local Time is: Sun Jun 1 13:08:13 2025 EEST
Firmware Updates (0x02): 1 Slot
Optional Admin Commands (0x0017): Security Format Frmw_DL Self_Test
Optional NVM Commands (0x005e): Wr_Unc DS_Mngmt Wr_Zero Sav/Sel_Feat Timestmp
Log Page Attributes (0x02): Cmd_Eff_Lg
Maximum Data Transfer Size: 32 Pages
Warning Comp. Temp. Threshold: 100 Celsius
Critical Comp. Temp. Threshold: 110 Celsius
Supported Power States
St Op Max Active Idle RL RT WL WT Ent_Lat Ex_Lat
0 + 8.00W - - 0 0 0 0 230000 50000
1 + 4.00W - - 1 1 1 1 4000 50000
2 + 3.00W - - 2 2 2 2 4000 250000
3 - 0.0300W - - 3 3 3 3 5000 10000
4 - 0.0050W - - 4 4 4 4 54000 45000
Supported LBA Sizes (NSID 0x1)
Id Fmt Data Metadt Rel_Perf
0 + 512 0 0
=== START OF SMART DATA SECTION ===
SMART overall-health self-assessment test result: PASSED
SMART/Health Information (NVMe Log 0x02, NSID 0xffffffff)
Critical Warning: 0x00
Temperature: 35 Celsius
Available Spare: 100%
Available Spare Threshold: 32%
Percentage Used: 0%
Data Units Read: 840,013 [430 GB]
Data Units Written: 1,699,047 [869 GB]
Host Read Commands: 7,031,574
Host Write Commands: 25,090,339
Controller Busy Time: 0
Power Cycles: 33
Power On Hours: 229
Unsafe Shutdowns: 23
Media and Data Integrity Errors: 0
Error Information Log Entries: 0
Warning Comp. Temperature Time: 0
Critical Comp. Temperature Time: 0
Error Information (NVMe Log 0x01, 8 of 8 entries)
No Errors Logged
Self-test Log (NVMe Log 0x06, NSID 0xffffffff)
Self-test status: No self-test in progress
No Self-tests Logged
Here, the only important values are:
Percentage Used, which is the percentage of used spare blocks. It should not exceed Available Spare Threshold, since that usually is the point of no return for the drive.Media and Data Integrity Errors, which indicate significant flash degredation.Error Information Log Entries, which usually indicate how many flash regions have been masked with spare flash.If you have just a few (<5) relocated sectors, it's probably fine to keep using the disk for a little while.
Using a few spare nvme flash blocks is also fine.
However burning through spare flash or rapidly relocating dozens of sectors is however a sign of imminent failure.
As the spare flash or sectors run out, the system's performance will rapidly degrade and filesystems like BTRFS will lock up, refusing to perform writes, refusing to corrupt the disk.