准備4塊40G磁盤做raid10，再准備一塊40G磁盤做備份盤，總共5塊40G磁盤
部署 RAID 10 磁盤陣列時，至少需要用 到 4 塊硬盤，還需要再加一塊備份硬盤，所以總計需要在虛擬機中模擬 5 塊硬盤設備
[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
現在創建一個 RAID 10 磁盤陣列+備份盤。在下面的命令中，參數-n 4 代表創建這個 RAID 10 磁盤陣列所需的硬盤數，參數-l 10 代表 RAID 的級別，而參數-x 1 則代表有一塊備 份盤。當查看/dev/md0（即 RAID 10 磁盤陣列的名稱）磁盤陣列的時候就能看到有一塊備 份盤在等待中了
現在將部署好的 RAID 5 磁盤陣列格式化為 ext4 文件格式，然后掛載到目錄上，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 ~]#
現在測試移除dev/sdb 這塊磁盤，可以看到/dev/sdf 頂替上去
[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
記得：寫入文件，永久生效