准备4块40G磁盘做raid10，再准备一块40G磁盘做备份盘，总共5块40G磁盘

部署 RAID 10 磁盘阵列时，至少需要用 到 4 块硬盘，还需要再加一块备份硬盘，所以总计需要在虚拟机中模拟 5 块硬盘设备

 

[root@bbb ~]# mdadm -Cv /dev/md0 -n 4 -l 10 -x 1 /dev/sdb /dev/sdc /dev/sdd /dev/sde /dev/sdf
mdadm: layout defaults to n2
mdadm: layout defaults to n2
mdadm: chunk size defaults to 512K
mdadm: size set to 41909248K
mdadm: Defaulting to version 1.2 metadata
mdadm: array /dev/md0 started.
[root@bbb ~]# mdadm -D /dev/md0 
/dev/md0:
           Version : 1.2
     Creation Time : Mon Sep 27 11:04:23 2021
        Raid Level : raid10
        Array Size : 83818496 (79.94 GiB 85.83 GB)
     Used Dev Size : 41909248 (39.97 GiB 42.92 GB)
      Raid Devices : 4
     Total Devices : 5
       Persistence : Superblock is persistent

       Update Time : Mon Sep 27 11:04:50 2021
             State : clean, resyncing 
    Active Devices : 4
   Working Devices : 5
    Failed Devices : 0
     Spare Devices : 1

            Layout : near=2
        Chunk Size : 512K

Consistency Policy : resync

     Resync Status : 11% complete

              Name : bbb.liutao.com:0  (local to host bbb.liutao.com)
              UUID : 61028f7c:a02fe686:1e041219:379c3607
            Events : 1

    Number   Major   Minor   RaidDevice State
       0       8       16        0      active sync set-A   /dev/sdb
       1       8       32        1      active sync set-B   /dev/sdc
       2       8       48        2      active sync set-A   /dev/sdd
       3       8       64        3      active sync set-B   /dev/sde

       4       8       80        -      spare   /dev/sdf

 

现在创建一个 RAID 10 磁盘阵列+备份盘。在下面的命令中，参数-n 4 代表创建这个 RAID 10 磁盘阵列所需的硬盘数，参数-l 10 代表 RAID 的级别，而参数-x 1 则代表有一块备 份盘。当查看/dev/md0（即 RAID 10 磁盘阵列的名称）磁盘阵列的时候就能看到有一块备 份盘在等待中了

 

现在将部署好的 RAID 5 磁盘阵列格式化为 ext4 文件格式，然后挂载到目录上，之后就 可以使用了

[root@bbb ~]# mkfs.ext4 /dev/md0 
mke2fs 1.42.9 (28-Dec-2013)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=128 blocks, Stripe width=256 blocks
5242880 inodes, 20954624 blocks
1047731 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=2168455168
640 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks: 
    32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, 
    4096000, 7962624, 11239424, 20480000

Allocating group tables: done                            
Writing inode tables: done                            
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done   

[root@bbb ~]#

 

现在测试移除dev/sdb 这块磁盘，可以看到/dev/sdf 顶替上去

[root@bbb ~]# mdadm /dev/md0 -f /dev/sdb
mdadm: set /dev/sdb faulty in /dev/md0
[root@bbb ~]# mdadm -D /dev/md0 
/dev/md0:
           Version : 1.2
     Creation Time : Mon Sep 27 11:04:23 2021
        Raid Level : raid10
        Array Size : 83818496 (79.94 GiB 85.83 GB)
     Used Dev Size : 41909248 (39.97 GiB 42.92 GB)
      Raid Devices : 4
     Total Devices : 5
       Persistence : Superblock is persistent

       Update Time : Mon Sep 27 11:11:01 2021
             State : clean, degraded, recovering 
    Active Devices : 3
   Working Devices : 4
    Failed Devices : 1
     Spare Devices : 1

            Layout : near=2
        Chunk Size : 512K

Consistency Policy : resync

    Rebuild Status : 2% complete

              Name : bbb.liutao.com:0  (local to host bbb.liutao.com)
              UUID : 61028f7c:a02fe686:1e041219:379c3607
            Events : 24

    Number   Major   Minor   RaidDevice State
       4       8       80        0      spare rebuilding   /dev/sdf
       1       8       32        1      active sync set-B   /dev/sdc
       2       8       48        2      active sync set-A   /dev/sdd
       3       8       64        3      active sync set-B   /dev/sde

       0       8       16        -      faulty   /dev/sdb

 

记得：写入文件，永久生效