raid管理工具-mdadm-管理raid1

raid1

RAID-1 ：mirroring（镜像卷）需要磁盘两块以上
原理:是把一个磁盘的数据镜像到另一个磁盘上，也就是说数据在写入一块磁盘的同时，会在另一块闲置的磁盘上生成镜像文件，(同步)
特性:当一块硬盘失效时，系统会忽略该硬盘，转而使用剩余的镜像盘读写数据，具备很好的磁盘冗余能力。

磁盘利用率为50%，即2块100G的磁盘构成RAID1只能提供100G的可用空间。

创建分区

[root@ 777 ~]# fdisk /dev/sdd

创建raid1

[root@ 777 ~]# mdadm -C -v /dev/md2  -l 1 -n 2 -x 1 /dev/sdd1 /dev/sdd[2,3]
mdadm: Note: this array has metadata at the start and
    may not be suitable as a boot device.  If you plan to
    store '/boot' on this device please ensure that
    your boot-loader understands md/v1.x metadata, or use
    --metadata=0.90
mdadm: size set to 3140608K
mdadm: largest drive (/dev/sdd1) exceeds size (3140608K) by more than 1%
Continue creating array? y
mdadm: Defaulting to version 1.2 metadata
mdadm: array /dev/md2 started.

将RAID1信息保存到配置文件中

[root@ 777 ~]# mdadm -Dsv > /etc/mdadm.conf

在raid设备上创建文件系统并挂载

[root@ 777 ~]# mkfs.xfs /dev/md2
meta-data=/dev/md2               isize=512    agcount=4, agsize=196288 blks
         =                       sectsz=512   attr=2, projid32bit=1
         =                       crc=1        finobt=0, sparse=0
data     =                       bsize=4096   blocks=785152, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0 ftype=1
log      =internal log           bsize=4096   blocks=2560, version=2
         =                       sectsz=512   sunit=0 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0
[root@centos7-xinsz08 ~]# mkdir /raid1
[root@centos7-xinsz08 ~]# mount /dev/md2 /raid1/

模拟损坏

[root@ 777 ~]#  mdadm /dev/md2 -f /dev/sdd1
mdadm: set /dev/sdd1 faulty in /dev/md2

[root@ 777 ~]#  mdadm  -D /dev/md2
/dev/md2:
           Version : 1.2
     Creation Time : Thu Feb 27 16:24:39 2020
        Raid Level : raid1
        Array Size : 3140608 (3.00 GiB 3.22 GB)
     Used Dev Size : 3140608 (3.00 GiB 3.22 GB)
      Raid Devices : 2
     Total Devices : 3
       Persistence : Superblock is persistent

       Update Time : Thu Feb 27 16:31:48 2020
             State : clean, degraded, recovering 
    Active Devices : 1
   Working Devices : 2
    Failed Devices : 1
     Spare Devices : 1

Consistency Policy : resync

    Rebuild Status : 88% complete

              Name : centos7-xinsz08:2  (local to host centos7-xinsz08)
              UUID : 5e197fe2:5c51970e:5e5288d5:e9066eb4
            Events : 35

    Number   Major   Minor   RaidDevice State
       2       8       51        0      spare rebuilding   /dev/sdd3
       1       8       50        1      active sync   /dev/sdd2

       0       8       49        -      faulty   /dev/sdd1

移除坏掉的设备

[root@centos7-xinsz08 raid1]# mdadm  -r /dev/md2 /dev/sdd1
mdadm: hot removed /dev/sdd1 from /dev/md2

raid1中一块硬盘坏了不影响raid正常运行
使用率是50%

来源：CSDN

作者：Permission_777

链接：https://blog.csdn.net/Permission_777/article/details/104542328

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