RAID10磁盘阵列由RAID1和RAID0组合而成，理论上只要不是RAID1磁盘阵列上的所有硬盘同时损坏，数据就不会丢失。也就是说最多可以在每个RAID1中损坏一个硬盘。
这里修复的实质是：使用新的硬盘代替磁盘阵列中损坏的硬盘，而在磁盘阵列损坏期间，并不影响使用。
1、查看测试的RAID10详细信息
[root@PC1linuxprobe dev]# mdadm -D /dev/md0 ## 查看测试的RAID10磁盘阵列详细信息，一共四块硬盘激活状态
/dev/md0:
Version : 1.2
Creation Time : Sun Nov 8 11:17:16 2020
Raid Level : raid10
Array Size : 41909248 (39.97 GiB 42.92 GB)
Used Dev Size : 20954624 (19.98 GiB 21.46 GB)
Raid Devices : 4
Total Devices : 4
Persistence : Superblock is persistent
Update Time : Sun Nov 8 11:20:45 2020
State : active
Active Devices : 4
Working Devices : 4
Failed Devices : 0
Spare Devices : 0
Layout : near=2
Chunk Size : 512K
Name : PC1linuxprobe:0 (local to host PC1linuxprobe)
UUID : 36866db8:2839f737:6831b810:d838b066
Events : 18
Number Major Minor RaidDevice State
0 8 16 0 active sync /dev/sdb
1 8 32 1 active sync /dev/sdc
2 8 48 2 active sync /dev/sdd
3 8 64 3 active sync /dev/sde
2、模拟损坏一块硬盘/dev/sdc
[root@PC1linuxprobe dev]# mdadm /dev/md0 -f /dev/sdc
mdadm: set /dev/sdc faulty in /dev/md0
[root@PC1linuxprobe dev]# mdadm -D /dev/md0
/dev/md0:
Version : 1.2
Creation Time : Sun Nov 8 11:17:16 2020
Raid Level : raid10
Array Size : 41909248 (39.97 GiB 42.92 GB)
Used Dev Size : 20954624 (19.98 GiB 21.46 GB)
Raid Devices : 4
Total Devices : 4
Persistence : Superblock is persistent
Update Time : Sun Nov 8 11:26:22 2020
State : active, degraded
Active Devices : 3
Working Devices : 3
Failed Devices : 1
Spare Devices : 0
Layout : near=2
Chunk Size : 512K
Name : PC1linuxprobe:0 (local to host PC1linuxprobe)
UUID : 36866db8:2839f737:6831b810:d838b066
Events : 20
Number Major Minor RaidDevice State
0 8 16 0 active sync /dev/sdb
1 0 0 1 removed
2 8 48 2 active sync /dev/sdd
3 8 64 3 active sync /dev/sde
1 8 32 - faulty /dev/sdc
损坏一块硬盘不影响RAID10磁盘阵列的使用，期间可以在/RAID10目录中创建或者删除文件。
3、重启系统（虚拟机）
4、查看此时RAID10磁盘阵列的详细信息
[root@PC1linuxprobe dev]# mdadm -D /dev/md0 ## 首先先查看当前RAID10磁盘阵列的详细信息
/dev/md0:
Version : 1.2
Creation Time : Sun Nov 8 11:17:16 2020
Raid Level : raid10
Array Size : 41909248 (39.97 GiB 42.92 GB)
Used Dev Size : 20954624 (19.98 GiB 21.46 GB)
Raid Devices : 4
Total Devices : 3
Persistence : Superblock is persistent
Update Time : Sun Nov 8 19:30:18 2020
State : clean, degraded
Active Devices : 3
Working Devices : 3
Failed Devices : 0
Spare Devices : 0
Layout : near=2
Chunk Size : 512K
Name : PC1linuxprobe:0 (local to host PC1linuxprobe)
UUID : 36866db8:2839f737:6831b810:d838b066
Events : 24
Number Major Minor RaidDevice State
0 8 16 0 active sync /dev/sdb
1 0 0 1 removed
2 8 48 2 active sync /dev/sdd
3 8 64 3 active sync /dev/sde
5、卸载
[root@PC1linuxprobe dev]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/rhel-root 18G 2.9G 15G 17% /
devtmpfs 985M 0 985M 0% /dev
tmpfs 994M 140K 994M 1% /dev/shm
tmpfs 994M 8.8M 986M 1% /run
tmpfs 994M 0 994M 0% /sys/fs/cgroup
/dev/md0 40G 49M 38G 1% /RAID10
/dev/sda1 497M 119M 379M 24% /boot
/dev/sr0 3.5G 3.5G 0 100% /run/media/root/RHEL-7.0 Server.x86_64
[root@PC1linuxprobe dev]# umount /RAID10
[root@PC1linuxprobe dev]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/rhel-root 18G 2.9G 15G 17% /
devtmpfs 985M 0 985M 0% /dev
tmpfs 994M 140K 994M 1% /dev/shm
tmpfs 994M 8.8M 986M 1% /run
tmpfs 994M 0 994M 0% /sys/fs/cgroup
/dev/sda1 497M 119M 379M 24% /boot
/dev/sr0 3.5G 3.5G 0 100% /run/media/root/RHEL-7.0 Server.x86_64
6、添加新硬盘（顶替损坏的硬盘）
[root@PC1linuxprobe dev]# mdadm /dev/md0 -a /dev/sdc ## 添加新硬盘
mdadm: added /dev/sdc
[root@PC1linuxprobe dev]# mdadm -D /dev/md0
/dev/md0:
Version : 1.2
Creation Time : Sun Nov 8 11:17:16 2020
Raid Level : raid10
Array Size : 41909248 (39.97 GiB 42.92 GB)
Used Dev Size : 20954624 (19.98 GiB 21.46 GB)
Raid Devices : 4
Total Devices : 4
Persistence : Superblock is persistent
Update Time : Sun Nov 8 11:37:41 2020
State : clean, degraded, recovering
Active Devices : 3
Working Devices : 4
Failed Devices : 0
Spare Devices : 1
Layout : near=2
Chunk Size : 512K
Rebuild Status : 16% complete
Name : PC1linuxprobe:0 (local to host PC1linuxprobe)
UUID : 36866db8:2839f737:6831b810:d838b066
Events : 32
Number Major Minor RaidDevice State
0 8 16 0 active sync /dev/sdb
4 8 32 1 spare rebuilding /dev/sdc
2 8 48 2 active sync /dev/sdd
3 8 64 3 active sync /dev/sde
[root@PC1linuxprobe dev]# mdadm -D /dev/md0
/dev/md0:
Version : 1.2
Creation Time : Sun Nov 8 11:17:16 2020
Raid Level : raid10
Array Size : 41909248 (39.97 GiB 42.92 GB)
Used Dev Size : 20954624 (19.98 GiB 21.46 GB)
Raid Devices : 4
Total Devices : 4
Persistence : Superblock is persistent
Update Time : Sun Nov 8 11:38:44 2020
State : clean, degraded, recovering
Active Devices : 3
Working Devices : 4
Failed Devices : 0
Spare Devices : 1
Layout : near=2
Chunk Size : 512K
Rebuild Status : 74% complete
Name : PC1linuxprobe:0 (local to host PC1linuxprobe)
UUID : 36866db8:2839f737:6831b810:d838b066
Events : 59
Number Major Minor RaidDevice State
0 8 16 0 active sync /dev/sdb
4 8 32 1 spare rebuilding /dev/sdc
2 8 48 2 active sync /dev/sdd
3 8 64 3 active sync /dev/sde
[root@PC1linuxprobe dev]# mdadm -D /dev/md0
/dev/md0:
Version : 1.2
Creation Time : Sun Nov 8 11:17:16 2020
Raid Level : raid10
Array Size : 41909248 (39.97 GiB 42.92 GB)
Used Dev Size : 20954624 (19.98 GiB 21.46 GB)
Raid Devices : 4
Total Devices : 4
Persistence : Superblock is persistent
Update Time : Sun Nov 8 11:39:11 2020
State : clean
Active Devices : 4
Working Devices : 4
Failed Devices : 0
Spare Devices : 0
Layout : near=2
Chunk Size : 512K
Name : PC1linuxprobe:0 (local to host PC1linuxprobe)
UUID : 36866db8:2839f737:6831b810:d838b066
Events : 69
Number Major Minor RaidDevice State
0 8 16 0 active sync /dev/sdb
4 8 32 1 active sync /dev/sdc
2 8 48 2 active sync /dev/sdd
3 8 64 3 active sync /dev/sde
7、重新挂载
[root@PC1linuxprobe dev]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/rhel-root 18G 2.9G 15G 17% /
devtmpfs 985M 0 985M 0% /dev
tmpfs 994M 140K 994M 1% /dev/shm
tmpfs 994M 8.8M 986M 1% /run
tmpfs 994M 0 994M 0% /sys/fs/cgroup
/dev/sda1 497M 119M 379M 24% /boot
/dev/sr0 3.5G 3.5G 0 100% /run/media/root/RHEL-7.0 Server.x86_64
[root@PC1linuxprobe dev]# cat /etc/fstab
#
# /etc/fstab
# Created by anaconda on Thu Nov 5 15:23:01 2020
#
# 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/rhel-root / xfs defaults 1 1
UUID=0ba20ae9-dd51-459f-ac48-7f7e81385eb8 /boot xfs defaults 1 2
/dev/mapper/rhel-swap swap swap defaults 0 0
/dev/md0 /RAID10 ext4 defaults 0 0
[root@PC1linuxprobe dev]# mount -a
[root@PC1linuxprobe dev]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/rhel-root 18G 2.9G 15G 17% /
devtmpfs 985M 0 985M 0% /dev
tmpfs 994M 140K 994M 1% /dev/shm
tmpfs 994M 8.8M 986M 1% /run
tmpfs 994M 0 994M 0% /sys/fs/cgroup
/dev/sda1 497M 119M 379M 24% /boot
/dev/sr0 3.5G 3.5G 0 100% /run/media/root/RHEL-7.0 Server.x86_64
/dev/md0 40G 49M 38G 1% /RAID10
8、总结RAID10磁盘阵列损坏的修复
- 首先重启系统，解除挂载
- 添加新硬盘 mdadm /dev/md0 -a /dev/newdisk
- 等待rebuilding完成，使用mdadm -D /dev/md0查看进度
- 重新挂载，mount -a （前提是已经写入开启自动挂载配置文件）