Масштабирование кластера Mariadb Galera

Я позволяю smartd регулярно проверять мои жесткие диски. Недавно я получил уведомление о неудачном коротком самотестировании одного из моих жестких драйверов.

 smartctl 6.4 2014-10-07 r4002 [x86_64-linux-3.16.0-0.bpo.4-amd64] (local build)
    Copyright (C) 2002-14, Bruce Allen, Christian Franke, www.smartmontools.org

    === START OF INFORMATION SECTION ===
    Model Family:     Western Digital RE4
    Device Model:     WDC WD1003FBYX-01Y7B0
    Serial Number:    WD-WCAW31677053
    LU WWN Device Id: 5 0014ee 25b0c013e
    Firmware Version: 01.01V01
    User Capacity:    1.000.204.886.016 bytes [1,00 TB]
    Sector Size:      512 bytes logical/physical
    Rotation Rate:    7200 rpm
    Device is:        In smartctl database [for details use: -P show]
    ATA Version is:   ATA8-ACS (minor revision not indicated)
SATA Version is:  SATA 2.6, 3.0 Gb/s
Local Time is:    Mon Dec  7 13:13:22 2015 CET
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:      (   0) The previous self-test routine completed
                                        without error or no self-test has ever 
                                        been run.
Total time to complete Offline 
data collection:                (16680) 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:        ( 172) minutes.
Conveyance self-test routine
recommended polling time:        (   5) minutes.
SCT capabilities:              (0x303f) 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   200   200   051    Pre-fail  Always       -       1
  3 Spin_Up_Time            0x0027   176   173   021    Pre-fail  Always       -       4191
  4 Start_Stop_Count        0x0032   100   100   000    Old_age   Always       -       37
  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   070   070   000    Old_age   Always       -       21991
     10 Spin_Retry_Count        0x0032   100   253   000    Old_age   Always       -       0
     11 Calibration_Retry_Count 0x0032   100   253   000    Old_age   Always       -       0
     12 Power_Cycle_Count       0x0032   100   100   000    Old_age   Always       -       37
    192 Power-Off_Retract_Count 0x0032   200   200   000    Old_age   Always       -       35
    193 Load_Cycle_Count        0x0032   200   200   000    Old_age   Always       -       1
    194 Temperature_Celsius     0x0022   110   088   000    Old_age   Always       -       37
    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

    SMART Error Log Version: 1
    No Errors Logged

    SMART Self-test log structure revision number 1
    Num  Test_Description    Status                  Remaining  LifeTime(hours)  LBA_of_first_error
    # 1  Short offline       Completed without error       00%     21981         -
    # 2  Extended offline    Completed without error       00%     21972         -
    # 3  Short offline       Completed without error       00%     21963         -
    # 4  Extended offline    Completed: read failure       90%     21934         4631341
    # 5  Short offline       Completed: read failure       50%     21933         4631341
    # 6  Short offline       Completed without error       00%     21909         -
    # 7  Short offline       Completed without error       00%     21885         -
    # 8  Short offline       Completed without error       00%     21861         -
    # 9  Short offline       Completed without error       00%     21837         -
    #10  Short offline       Completed without error       00%     21813         -
    #11  Short offline       Completed without error       00%     21789         -
    #12  Extended offline    Completed without error       00%     21769         -
    #13  Short offline       Completed without error       00%     21765         -
    #14  Short offline       Completed without error       00%     21742         -
    #15  Short offline       Completed without error       00%     21718         -
    #16  Short offline       Completed without error       00%     21694         -
    #17  Short offline       Completed without error       00%     21670         -
    #18  Short offline       Completed without error       00%     21646         -
    #19  Short offline       Completed without error       00%     21622         -
    #20  Extended offline    Completed without error       00%     21602         -
    #21  Short offline       Completed without error       00%     21598         -
    2 of 2 failed self-tests are outdated by newer successful extended offline self-test # 2

    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.

Затем я запустил расширенное автономное самотестирование, которое также прервалось из-за сбоя чтения на том же LBA. Затем я удалил диск из mdadm-raid и начал деструктивный тест с плохими блоками - он прошел три раза, и на удивление никаких ошибок не было обнаружено. После очередного самотестирования количество ошибок в журнале уменьшилось до 0.

Мой диск меня обманывает? (Это Western Digital RE4.) Он не сообщает о Current_Pending_Sector, Offline_Uncorrectable или Reallocated_Event_Count. Он сообщает 1 для Raw_Read_Error_Rate и 1 для Multi_Zone_Error_Rate, но теперь он снова равен 0.

Я заменю диск, но не уверен, стоит ли переоценивать свое предположение о надежности расширенного автономного самотестирования.