raid与备份盘

raid与备份盘学习

1、还是使用刚才的四块硬盘做实验，三块盘搭建raid阵列组，有一个块当做备份盘，可以使用raid5来搭建三块硬盘的阵列组

[root@WALKER ~]# mdadm -Cv /dev/md0 -n 3 -l 5 -x 1 /dev/sdb /dev/sdc /dev/sdd /dev/sde
mdadm: layout defaults to left-symmetric
mdadm: layout defaults to left-symmetric
mdadm: chunk size defaults to 512K
mdadm: /dev/sdb appears to contain an ext2fs file system
size=20971520K mtime=Thu Jan 1 08:00:00 1970
mdadm: partition table exists on /dev/sdb
mdadm: partition table exists on /dev/sdb but will be lost or
meaningless after creating array
mdadm: size set to 10468352K
mdadm: largest drive (/dev/sdb) exceeds size (10468352K) by more than 1%
Continue creating array? y
mdadm: Defaulting to version 1.2 metadata
mdadm: array /dev/md0 started.

[root@WALKER ~]# mdadm -Cv /dev/md0 -n 3 -l 5 -x 1 /dev/sdb /dev/sdc /dev/sdd /dev/sde

参数解释：

-n 3：指定三块硬盘

-l 5：指定raid的级别是raid5

-x 1：指定一个备份盘

/dev/sd[b-e]：指定使用的四块硬盘

2、检查一下raid的阵列组信息与状态

[root@WALKER ~]# mdadm -D /dev/md0
/dev/md0:
           Version : 1.2
     Creation Time : Sun May 22 17:32:23 2022
        Raid Level : raid5
        Array Size : 20936704 (19.97 GiB 21.44 GB)
     Used Dev Size : 10468352 (9.98 GiB 10.72 GB)
      Raid Devices : 3
     Total Devices : 4
       Persistence : Superblock is persistent

       Update Time : Sun May 22 17:33:16 2022
             State : clean
    Active Devices : 3
   Working Devices : 4
    Failed Devices : 0
     Spare Devices : 1

            Layout : left-symmetric
        Chunk Size : 512K

Consistency Policy : resync

              Name : WALKER:0 (local to host WALKER)
              UUID : 092c3ea1:dced5583:3c22d126:699a2102
            Events : 18

    Number   Major   Minor   RaidDevice State
       0       8       16        0      active sync   /dev/sdb
       1       8       32        1      active sync   /dev/sdc
       4       8       48        2      active sync   /dev/sdd

       3       8       64        -      spare   /dev/sde
[root@WALKER ~]#

3、针对阵列组格式化文件系统

[root@WALKER ~]# mkfs.xfs -f /dev/md0
meta-data=/dev/md0               isize=512    agcount=16, agsize=327040 blks
         =                       sectsz=512   attr=2, projid32bit=1
         =                       crc=1        finobt=0, sparse=0
data     =                       bsize=4096   blocks=5232640, imaxpct=25
         =                       sunit=128    swidth=256 blks
naming   =version 2              bsize=4096   ascii-ci=0 ftype=1
log      =internal log           bsize=4096   blocks=2560, version=2
         =                       sectsz=512   sunit=8 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0
[root@WALKER ~]#

4、开始挂载使用阵列组

[root@WALKER ~]# ls /mdadm/
[root@WALKER ~]# mount /dev/md0 /mdadm/
mount: /dev/md0 已经挂载或 /mdadm 忙
/dev/md0 已经挂载到 /mdadm 上
[root@WALKER ~]#

5、检查挂载情况，以及数据写入情况

[root@WALKER ~]# mount -l |grep md0
/dev/md0 on /mdadm type xfs (rw,relatime,seclabel,attr2,inode64,sunit=1024,swidth=2048,noquota)
[root@WALKER ~]# ls /mdadm/
[root@WALKER ~]#
[root@WALKER ~]# df -hT
文件系统类型容量已用可用已用% 挂载点
/dev/md0 xfs 20G 33M 20G 1% /mdadm
[root@WALKER ~]#

6、此时可以写入数据检查raid是否可以正常使用

[root@WALKER ~]# cd /mdadm/
[root@WALKER mdadm]# ls
[root@WALKER mdadm]# echo {1..1000000} > test.txt
[root@WALKER mdadm]# cp test.txt test1.txt
[root@WALKER mdadm]# cp test.txt test2.txt
[root@WALKER mdadm]# cp test.txt test3.txt
[root@WALKER mdadm]# cp test.txt test4.txt
[root@WALKER mdadm]# df -hT
文件系统类型容量已用可用已用% 挂载点
/dev/md0 xfs 20G 66M 20G 1% /mdadm
[root@WALKER mdadm]#

7、见证备份磁盘的作用

从磁盘阵列组中删除一块硬盘，检查阵列情况

[root@WALKER mdadm]# mdadm /dev/md0 -f /dev/sdb
mdadm: set /dev/sdb faulty in /dev/md0
[root@WALKER mdadm]#

8、检查备份盘是否自动加入阵列组，实验完成！

[root@WALKER mdadm]# mdadm -D /dev/md0
/dev/md0:
           Version : 1.2
     Creation Time : Sun May 22 17:32:23 2022
        Raid Level : raid5
        Array Size : 20936704 (19.97 GiB 21.44 GB)
     Used Dev Size : 10468352 (9.98 GiB 10.72 GB)
      Raid Devices : 3
     Total Devices : 4
       Persistence : Superblock is persistent

       Update Time : Sun May 22 17:53:10 2022
             State : clean
    Active Devices : 3
   Working Devices : 3
    Failed Devices : 1
     Spare Devices : 0

            Layout : left-symmetric
        Chunk Size : 512K

Consistency Policy : resync

              Name : WALKER:0 (local to host WALKER)
              UUID : 092c3ea1:dced5583:3c22d126:699a2102
            Events : 41

    Number   Major   Minor   RaidDevice State
       3       8       64        0      active sync   /dev/sde
       1       8       32        1      active sync   /dev/sdc
       4       8       48        2      active sync   /dev/sdd

       0       8       16        -      faulty   /dev/sdb
[root@WALKER mdadm]#