Hey, I tested my hard drives with smartctl -a. And for 199 UDMA_CRC_Error_Count I get a raw value of 808. Should I worry about this disk? I'll post you below the whole output of smartctl -a. Someone said it could be a CRC-Failure. But I don't know exactly what this means. This is my backup drive. So it would be critical if it is something wrong with this disk. smartctl -a /dev/sdd1 smartctl 6.4 2015-06-04 r4109 [x86_64-linux-4.1.2-2-ARCH] (local build) Copyright (C) 2002-15, Bruce Allen, Christian Franke, www.smartmontools.org === START OF INFORMATION SECTION === Model Family: Seagate SV35 Device Model: ST2000VX000-1ES164 Serial Number: Z4Z1JHXZ LU WWN Device Id: 5 000c50 079dbcc19 Firmware Version: CV26 User Capacity: 2.000.398.934.016 bytes [2,00 TB] Sector Sizes: 512 bytes logical, 4096 bytes physical Rotation Rate: 7200 rpm Form Factor: 3.5 inches Device is: In smartctl database [for details use: -P show] ATA Version is: ACS-2, ACS-3 T13/2161-D revision 3b SATA Version is: SATA 3.1, 6.0 Gb/s (current: 6.0 Gb/s) Local Time is: Fri Jul 24 12:39:16 2015 CEST 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: (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: ( 80) seconds. Offline data collection capabilities: (0x73) SMART execute Offline immediate. Auto Offline data collection on/off support. Suspend Offline collection upon new command. No 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: ( 1) minutes. Extended self-test routine recommended polling time: ( 217) minutes. Conveyance self-test routine recommended polling time: ( 2) minutes. SCT capabilities: (0x10b9) SCT Status supported. SCT Error Recovery Control supported. SCT Feature Control supported. SCT Data Table supported. SMART Attributes Data Structure revision number: 10 Vendor Specific SMART Attributes with Thresholds: ID# ATTRIBUTE_NAME FLAG VALUE WORST THRESH TYPE UPDATED WHEN_FAILED RAW_VALUE 1 Raw_Read_Error_Rate 0x000f 119 099 006 Pre-fail Always - 212390608 3 Spin_Up_Time 0x0003 096 096 000 Pre-fail Always - 0 4 Start_Stop_Count 0x0032 100 100 020 Old_age Always - 470 5 Reallocated_Sector_Ct 0x0033 100 100 010 Pre-fail Always - 0 7 Seek_Error_Rate 0x000f 100 253 030 Pre-fail Always - 654069 9 Power_On_Hours 0x0032 099 099 000 Old_age Always - 941 10 Spin_Retry_Count 0x0013 100 100 097 Pre-fail Always - 0 12 Power_Cycle_Count 0x0032 100 100 020 Old_age Always - 384 184 End-to-End_Error 0x0032 100 100 099 Old_age Always - 0 187 Reported_Uncorrect 0x0032 100 100 000 Old_age Always - 0 188 Command_Timeout 0x0032 100 098 000 Old_age Always - 48 189 High_Fly_Writes 0x003a 092 092 000 Old_age Always - 8 190 Airflow_Temperature_Cel 0x0022 070 055 045 Old_age Always - 30 (Min/Max 27/30) 191 G-Sense_Error_Rate 0x0032 100 100 000 Old_age Always - 0 192 Power-Off_Retract_Count 0x0032 100 100 000 Old_age Always - 26 193 Load_Cycle_Count 0x0032 100 100 000 Old_age Always - 474 194 Temperature_Celsius 0x0022 030 045 000 Old_age Always - 30 (0 13 0 0 0) 197 Current_Pending_Sector 0x0012 100 100 000 Old_age Always - 0 198 Offline_Uncorrectable 0x0010 100 100 000 Old_age Offline - 0 199 UDMA_CRC_Error_Count 0x003e 200 182 000 Old_age Always - 808 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.