CentOS Raid5故障导致进入救援模式处理

前言

服务器断电后Raid故障，导致开机进入紧急救援模式，相关服务无法启动

处理过程

journalctl -xb 查看日志

journalctl -xb

往下翻关注红色的字，看到是raid在报错，

取消raid开机挂载

修改/etc/fstab 取消raid挂载，这样就可以重启进入系统了

[root@192 ~]# cat /etc/fstab

#
# /etc/fstab
# Created by anaconda on Fri Jul  5 06:41:45 2024
#
# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
/dev/mapper/centos-root /                       xfs     defaults        0 0
UUID=1d3a5601-d085-4d87-b418-63e9d48aa2e4 /boot                   xfs     defaults        0 0
#UUID=7af86e80-718d-4cc5-8556-a0c58c6bb760 /mnt/raid5 ext4 defaults 0 2
UUID=525E-341C          /boot/efi               vfat    umask=0077,shortname=winnt 0 0
/dev/mapper/centos-home /home                   xfs     defaults        0 0
/dev/mapper/centos-swap swap                    swap    defaults        0 0
[root@192 ~]# 

直接在fstab里注释掉raid盘，然后保存重启

查看raid状态

[root@192 ~]#  mdadm --detail /dev/md0
/dev/md0:
           Version : 1.2
     Creation Time : Fri Jul  5 07:27:37 2024
        Raid Level : raid5
     Used Dev Size : 18446744073709551615
      Raid Devices : 5
     Total Devices : 5
       Persistence : Superblock is persistent

       Update Time : Sun Jul  7 00:19:08 2024
             State : active, FAILED, Not Started 
    Active Devices : 4
   Working Devices : 5
    Failed Devices : 0
     Spare Devices : 1

            Layout : left-symmetric
        Chunk Size : 512K

Consistency Policy : unknown

              Name : localhost.localdomain:0
              UUID : 3302b9f5:f38071b2:dc13cf9b:5356f797
            Events : 192610

    Number   Major   Minor   RaidDevice State
       -       0        0        0      removed
       -       0        0        1      removed
       -       0        0        2      removed
       -       0        0        3      removed
       -       0        0        4      removed

       -       8        0        0      sync   /dev/sda
       -       8       16        1      sync   /dev/sdb
       -       8       32        2      sync   /dev/sdc
       -       8       48        3      sync   /dev/sdd
       -       8       64        4      spare rebuilding   /dev/sde

raid处在faild状态

暂停raid

[root@192 ~]# sudo mdadm --stop /dev/md0
mdadm: stopped /dev/md0

清空0字节块

[root@192 ~]# sudo mdadm --zero-superblock /dev/sda
[root@192 ~]# sudo mdadm --zero-superblock /dev/sdb
[root@192 ~]# sudo mdadm --zero-superblock /dev/sdc
[root@192 ~]# sudo mdadm --zero-superblock /dev/sdd
[root@192 ~]# sudo mdadm --zero-superblock /dev/sde

重建raid

[root@192 ~]# sudo mdadm --create /dev/md0 --level=5 --raid-devices=5 /dev/sda /dev/sdb /dev/sdc /dev/sdd /dev/sde
mdadm: partition table exists on /dev/sda
mdadm: partition table exists on /dev/sda but will be lost or
       meaningless after creating array
mdadm: partition table exists on /dev/sdb
mdadm: partition table exists on /dev/sdb but will be lost or
       meaningless after creating array
mdadm: partition table exists on /dev/sdc
mdadm: partition table exists on /dev/sdc but will be lost or
       meaningless after creating array
mdadm: partition table exists on /dev/sdd
mdadm: partition table exists on /dev/sdd but will be lost or
       meaningless after creating array
mdadm: partition table exists on /dev/sde
mdadm: partition table exists on /dev/sde but will be lost or
       meaningless after creating array
Continue creating array? 
Continue creating array? (y/n) y
mdadm: Defaulting to version 1.2 metadata
mdadm: array /dev/md0 started.

查看raid状态

[root@192 ~]# sudo mdadm --detail /dev/md0
/dev/md0:
           Version : 1.2
     Creation Time : Sun Jul  7 19:01:16 2024
        Raid Level : raid5
        Array Size : 23441561600 (21.83 TiB 24.00 TB)
     Used Dev Size : 5860390400 (5.46 TiB 6.00 TB)
      Raid Devices : 5
     Total Devices : 5
       Persistence : Superblock is persistent

     Intent Bitmap : Internal

       Update Time : Sun Jul  7 19:01:21 2024
             State : clean, degraded, recovering 
    Active Devices : 4
   Working Devices : 5
    Failed Devices : 0
     Spare Devices : 1

            Layout : left-symmetric
        Chunk Size : 512K

Consistency Policy : bitmap

    Rebuild Status : 0% complete

              Name : 192.168.10.240:0  (local to host 192.168.10.240)
              UUID : cf4c90df:b1b909d8:ef892cd0:537f8e83
            Events : 2

    Number   Major   Minor   RaidDevice State
       0       8        0        0      active sync   /dev/sda
       1       8       16        1      active sync   /dev/sdb
       2       8       32        2      active sync   /dev/sdc
       3       8       48        3      active sync   /dev/sdd
       5       8       64        4      spare rebuilding   /dev/sde

raid状态正常了，其他步骤可以按照建立raid一样来了。