How to replace disk in RAID5 when resync in progress

    • OMV 3.x
    • How to replace disk in RAID5 when resync in progress

      Hello!
      I have 4 x WD30EFRX in RAID5 soft array.
      Now array in resync status:
      Display Spoiler

      root@OpenMediaVault:~# cat /proc/mdstat
      Personalities : [raid6] [raid5] [raid4]
      md0 : active raid5 sda[0] sdd[3] sdc[2] sdb[1]
      8790405120 blocks super 1.2 level 5, 512k chunk, algorithm 2 [4/4] [UUUU]
      [===================>.] resync = 99.6% (2919278728/2930135040) finish=852.3min speed=212K/sec

      unused devices: <none>
      root@OpenMediaVault:~#

      It seems that resync can't be done because /dev/sdb stops responding on command smartctl -a /dev/sdb. Other disks are responding on it.
      The last result of this command:
      Display Spoiler

      root@OpenMediaVault:~# smartctl -a /dev/sdb
      smartctl 6.4 2014-10-07 r4002 [x86_64-linux-4.9.0-0.bpo.3-amd64] (local build)
      Copyright (C) 2002-14, Bruce Allen, Christian Franke, smartmontools.org

      === START OF INFORMATION SECTION ===
      Model Family: Western Digital Red
      Device Model: WDC WD30EFRX-68EUZN0
      Serial Number: WD-WCC4NHZDPSKE
      LU WWN Device Id: 5 0014ee 20ace3516
      Firmware Version: 82.00A82
      User Capacity: 3,000,592,982,016 bytes [3.00 TB]
      Sector Sizes: 512 bytes logical, 4096 bytes physical
      Rotation Rate: 5400 rpm
      Device is: In smartctl database [for details use: -P show]
      ATA Version is: ACS-2 (minor revision not indicated)
      SATA Version is: SATA 3.0, 6.0 Gb/s (current: 3.0 Gb/s)
      Local Time is: Sat Sep 9 23:44:08 2017 MSK
      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: (0x85) Offline data collection activity
      was aborted by an interrupting command from host.
      Auto Offline Data Collection: Enabled.
      Self-test execution status: ( 241) Self-test routine in progress...
      10% of test remaining.
      Total time to complete Offline
      data collection: (39360) 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: ( 395) minutes.
      Conveyance self-test routine
      recommended polling time: ( 5) minutes.
      SCT capabilities: (0x703d) 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 199 199 051 Pre-fail Always - 47100
      3 Spin_Up_Time 0x0027 178 177 021 Pre-fail Always - 6066
      4 Start_Stop_Count 0x0032 100 100 000 Old_age Always - 642
      5 Reallocated_Sector_Ct 0x0033 200 200 140 Pre-fail Always - 0
      7 Seek_Error_Rate 0x002e 200 200 000 Old_age Always - 0
      9 Power_On_Hours 0x0032 088 088 000 Old_age Always - 8948
      10 Spin_Retry_Count 0x0032 100 100 000 Old_age Always - 0
      11 Calibration_Retry_Count 0x0032 100 100 000 Old_age Always - 0
      12 Power_Cycle_Count 0x0032 100 100 000 Old_age Always - 642
      192 Power-Off_Retract_Count 0x0032 200 200 000 Old_age Always - 6
      193 Load_Cycle_Count 0x0032 200 200 000 Old_age Always - 993
      194 Temperature_Celsius 0x0022 115 113 000 Old_age Always - 35
      196 Reallocated_Event_Count 0x0032 200 200 000 Old_age Always - 0
      197 Current_Pending_Sector 0x0032 200 200 000 Old_age Always - 0
      198 Offline_Uncorrectable 0x0030 200 200 000 Old_age Offline - 0
      199 UDMA_CRC_Error_Count 0x0032 200 200 000 Old_age Always - 0
      200 Multi_Zone_Error_Rate 0x0008 200 200 000 Old_age Offline - 0

      <CUT>

      I have new disk for replace, but how to safely replace /dev/sdb without data loss?
    • New

      Re,

      it depends ... on which drive the resync started. If the resync-causing error comes from drive sdb, the you can change that drive - but you have to be very careful!
      (1st you have to mark the drive manually as "failed" the wait until the array calms down ... then swap and rebuild ...)

      Check the logs, what causes the resync and check the logs for (other) drive errors ... then backup your data and then you can try to swap the drive.

      Sc0rp
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