What do the fstab mount options ‘errors=remount -ro’ mean?
errors=remount-ro 0 1 concerns me because I would expect defaults instead of errors=remount-ro . Ubuntu runs as normal, but I have reasons to believe that Ubuntu might have being tempered with during the install process. So what does this mean?
3 Answers 3
errors= Define the behavior when an error is encountered. (Either ignore errors and just mark the filesystem erroneous and continue, or remount the filesystem read-only, or panic and halt the system.) The default is set in the filesystem superblock, and can be changed using tune2fs(8).
Essentially, when there is an error mounting the disk with read/write privileges, it will instead mount it as ‘read only’.
Whether or not ‘defaults’ are used in your setup are not necessarily relevant. Yes, you can expect ‘defaults’ here, but the lack therein doesn’t hurt you a ton.
As well, the ‘0 1’ part isn’t part of the mount options — everything in an fstab line is space-delimited / tab-delimited — any space between things indicates the ‘next argument’ to use.
As a security person, though, my advice is that if you believe your system was tampered with during installation outside that of the typical installer, then you should not be using that system, and should install with a known, good ISO and no networking during that installation to rule out network boot installer images causing issues.
How to deal with errors=remount-ro?
You are in emergency mode, After logging in type «journalctl -xb» to view system logs, «systemctl reboot» to reboot, «systemctl default» or «exit» to boot into default mode. Press enter for maintenance (or press control-D to contnue):
Following helped me getting rid of emergency mode fsck -y /dev/sda* *First I used sda7 but boot was successful for only one time and again entered into emergency mode, then i used sda5 and sda7 one by one. It worked for me but by applying command nano /etc/fstab or vi /etc/fstab , output is annoying as it says / file was on /dev/sda5 during installation ext4 errors=remount-ro 0 1 How to deal with errors=remount-ro ? I don’t know if it might harm my system. OS = UBUNTU 18.04 Smartmontools result:
=== START OF READ SMART DATA SECTION === SMART overall-health self-assessment test result: PASSED General SMART Values: Offline data collection status: (0x80) Offline data collection activity was never started. Auto Offline Data Collection: Enabled. Self-test execution status: ( 121) The previous self-test completed having the read element of the test failed. Total time to complete Offline data collection: ( 120) seconds. Offline data collection capabilities: (0x51) SMART execute Offline immediate. No Auto Offline data collection support. Suspend Offline collection upon new command. No 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: ( 2) minutes. Extended self-test routine recommended polling time: ( 105) 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 0x002f 100 100 050 Pre-fail Always - 0 2 Throughput_Performance 0x0027 100 100 050 Pre-fail Always - 0 3 Spin_Up_Time 0x0023 100 100 002 Pre-fail Always - 1368 4 Start_Stop_Count 0x0032 100 100 000 Old_age Always - 5899 5 Reallocated_Sector_Ct 0x0033 100 100 010 Pre-fail Always - 8 7 Seek_Error_Rate 0x002f 100 100 050 Pre-fail Always - 0 8 Seek_Time_Performance 0x0025 100 100 050 Pre-fail Offline - 0 9 Power_On_Hours 0x0032 061 061 000 Old_age Always - 15756 10 Spin_Retry_Count 0x0033 217 100 030 Pre-fail Always - 0 12 Power_Cycle_Count 0x0032 100 100 000 Old_age Always - 5587 183 Runtime_Bad_Block 0x0032 100 100 001 Old_age Always - 0 184 End-to-End_Error 0x0033 100 100 097 Pre-fail Always - 0 185 Unknown_Attribute 0x0032 100 100 001 Old_age Always - 65535 187 Reported_Uncorrect 0x0032 001 001 000 Old_age Always - 24102 188 Command_Timeout 0x0032 100 099 000 Old_age Always - 8 189 High_Fly_Writes 0x003a 100 100 001 Old_age Always - 0 190 Airflow_Temperature_Cel 0x0022 063 045 040 Old_age Always - 37 (Min/Max 30/39) 191 G-Sense_Error_Rate 0x0032 100 100 000 Old_age Always - 563 192 Power-Off_Retract_Count 0x0022 100 100 000 Old_age Always - 23069024 193 Load_Cycle_Count 0x0032 070 070 000 Old_age Always - 308244 194 Temperature_Celsius 0x0022 063 045 040 Old_age Always - 37 (Min/Max 30/39) 196 Reallocated_Event_Count 0x0032 100 100 000 Old_age Always - 1 197 Current_Pending_Sector 0x0032 100 100 000 Old_age Always - 3320 199 UDMA_CRC_Error_Count 0x0032 200 200 000 Old_age Always - 0 SMART Error Log Version: 1 ATA Error Count: 25061 (device log contains only the most recent five errors) CR = Command Register [HEX] FR = Features Register [HEX] SC = Sector Count Register [HEX] SN = Sector Number Register [HEX] CL = Cylinder Low Register [HEX] CH = Cylinder High Register [HEX] DH = Device/Head Register [HEX] DC = Device Command Register [HEX] ER = Error register [HEX] ST = Status register [HEX] Powered_Up_Time is measured from power on, and printed as DDd+hh:mm:SS.sss where DD=days, hh=hours, mm=minutes, SS=sec, and sss=millisec. It "wraps" after 49.710 days. Error 25061 occurred at disk power-on lifetime: 15747 hours (656 days + 3 hours) When the command that caused the error occurred, the device was active or idle. After command completion occurred, registers were: ER ST SC SN CL CH DH -- -- -- -- -- -- -- 40 41 50 ae 2c 01 40 Error: UNC at LBA = 0x00012cae = 76974 Commands leading to the command that caused the error were: CR FR SC SN CL CH DH DC Powered_Up_Time Command/Feature_Name -- -- -- -- -- -- -- -- ---------------- -------------------- 60 80 58 00 2d 01 40 00 01:24:48.589 READ FPDMA QUEUED 60 80 50 80 2c 01 40 00 01:24:48.558 READ FPDMA QUEUED 60 80 48 00 2c 01 40 00 01:24:48.558 READ FPDMA QUEUED 60 80 40 80 2b 01 40 00 01:24:48.558 READ FPDMA QUEUED 60 80 38 00 2b 01 40 00 01:24:48.557 READ FPDMA QUEUED Error 25060 occurred at disk power-on lifetime: 15745 hours (656 days + 1 hours) When the command that caused the error occurred, the device was active or idle. After command completion occurred, registers were: ER ST SC SN CL CH DH -- -- -- -- -- -- -- 40 41 f0 ae 2c 01 40 Error: UNC at LBA = 0x00012cae = 76974 Commands leading to the command that caused the error were: CR FR SC SN CL CH DH DC Powered_Up_Time Command/Feature_Name -- -- -- -- -- -- -- -- ---------------- -------------------- 60 80 f8 60 9f 50 40 00 00:00:20.324 READ FPDMA QUEUED 60 01 f0 ae 2c 01 40 00 00:00:20.277 READ FPDMA QUEUED 60 80 e8 e0 9e 50 40 00 00:00:20.277 READ FPDMA QUEUED 60 80 e0 60 9e 50 40 00 00:00:20.277 READ FPDMA QUEUED 2f 00 01 10 00 00 28 00 00:00:20.276 READ LOG EXT Error 25059 occurred at disk power-on lifetime: 15745 hours (656 days + 1 hours) When the command that caused the error occurred, the device was active or idle. After command completion occurred, registers were: ER ST SC SN CL CH DH -- -- -- -- -- -- -- 40 41 d8 ae 2c 01 40 Error: UNC at LBA = 0x00012cae = 76974 Commands leading to the command that caused the error were: CR FR SC SN CL CH DH DC Powered_Up_Time Command/Feature_Name -- -- -- -- -- -- -- -- ---------------- -------------------- 60 01 d8 ae 2c 01 40 00 00:00:20.185 READ FPDMA QUEUED 60 02 d0 32 2c 01 40 00 00:00:20.185 READ FPDMA QUEUED 60 02 c8 30 2c 01 40 00 00:00:20.185 READ FPDMA QUEUED 61 08 c0 38 75 03 40 00 00:00:20.184 WRITE FPDMA QUEUED 60 3d b8 71 2c 01 40 00 00:00:20.169 READ FPDMA QUEUED Error 25058 occurred at disk power-on lifetime: 15744 hours (656 days + 0 hours) When the command that caused the error occurred, the device was active or idle. After command completion occurred, registers were: ER ST SC SN CL CH DH -- -- -- -- -- -- -- 40 41 18 ae 2c 01 40 Error: UNC at LBA = 0x00012cae = 76974 Commands leading to the command that caused the error were: CR FR SC SN CL CH DH DC Powered_Up_Time Command/Feature_Name -- -- -- -- -- -- -- -- ---------------- -------------------- 60 01 18 ae 2c 01 40 00 00:00:20.376 READ FPDMA QUEUED 60 80 10 c0 bf 2e 40 00 00:00:20.376 READ FPDMA QUEUED 60 80 08 40 bf 2e 40 00 00:00:20.376 READ FPDMA QUEUED 2f 00 01 10 00 00 28 00 00:00:20.370 READ LOG EXT 60 80 08 40 bf 2e 40 00 00:00:20.329 READ FPDMA QUEUED Error 25057 occurred at disk power-on lifetime: 15744 hours (656 days + 0 hours) When the command that caused the error occurred, the device was active or idle. After command completion occurred, registers were: ER ST SC SN CL CH DH -- -- -- -- -- -- -- 40 41 00 ae 2c 01 40 Error: UNC at LBA = 0x00012cae = 76974 Commands leading to the command that caused the error were: CR FR SC SN CL CH DH DC Powered_Up_Time Command/Feature_Name -- -- -- -- -- -- -- -- ---------------- -------------------- 60 01 00 ae 2c 01 40 00 00:00:20.291 READ FPDMA QUEUED 60 02 f8 32 2c 01 40 00 00:00:20.291 READ FPDMA QUEUED 60 02 f0 30 2c 01 40 00 00:00:20.291 READ FPDMA QUEUED 61 08 e8 38 75 03 40 00 00:00:20.290 WRITE FPDMA QUEUED 60 3d e0 71 2c 01 40 00 00:00:20.275 READ FPDMA QUEUED SMART Self-test log structure revision number 1 Num Test_Description Status Remaining LifeTime(hours) LBA_of_first_error # 1 Extended offline Completed: read failure 90% 15753 76974 # 2 Extended offline Aborted by host 40% 31 - # 3 Short offline Completed without error 00% 30 - # 4 Extended offline Completed without error 00% 30 - # 5 Short offline Completed without error 00% 28 - 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.