1、主要性能排序：
    冗余从好到坏：raid 1 raid 10 raid 5 raid 0
    性能从好到坏：raid 0 raid 10 raid 5 raid 1
    成本从低到高：raid 0 raid 5 raid 1 raid 10
    image.png
    image.png
    操作步骤
    一： 划分磁盘（磁盘分区）

    1. [root@linux001 ~]# fdisk /dev/sdb
    2. Welcome to fdisk (util-linux 2.23.2).
    4. Changes will remain in memory only, until you decide to write them.
    5. Be careful before using the write command.
    8. Command (m for help): n
    9. Partition type:
    10.    p   primary (0 primary, 0 extended, 4 free)
    11.    e   extended
    12. Select (default p): p
    13. Partition number (1-4, default 1):
    14. First sector (2048-41943039, default 2048):
    15. Using default value 2048
    16. Last sector, +sectors or +size{K,M,G} (2048-41943039, default 41943039): +200M
    17. Partition 1 of type Linux and of size 200 MiB is set
    19. Command (m for help): t                                    #修改文件格式为fd
    20. Selected partition 1
    21. Hex code (type L to list all codes): fd
    22. Changed type of partition 'Linux' to 'Linux raid autodetect'
    24. Command (m for help): p
    26. Disk /dev/sdb: 21.5 GB, 21474836480 bytes, 41943040 sectors
    27. Units = sectors of 1 * 512 = 512 bytes
    28. Sector size (logical/physical): 512 bytes / 512 bytes
    29. I/O size (minimum/optimal): 512 bytes / 512 bytes
    30. Disk label type: dos
    31. Disk identifier: 0x0bf1ea4a
    33.    Device Boot      Start         End      Blocks   Id  System
    34. /dev/sdb1            2048      411647      204800   fd  Linux raid autodetect
    36. Command (m for help): w
    37. The partition table has been altered!
    39. Calling ioctl() to re-read partition table.
    40. Syncing disks.

    使用同样的方法创建其他3个硬盘分区

    1. [root@linux001 ~]# fdisk -l                        （以去除无用信息）
    3.    Device Boot      Start         End      Blocks   Id  System
    4. /dev/sdb1            2048      411647      204800   fd  Linux raid autodetect
    6. /dev/sdc1            2048      411647      204800   fd  Linux raid autodetect
    8. /dev/sdd1            2048      411647      204800   fd  Linux raid autodetect
    10. /dev/sde1            2048      411647      204800   fd  Linux raid autodetect

    二： 使用mdadm命令创建RAID5
    RAID的设备名称为/dev/mdx ,其中X为序列号从0开始

    1. [root@linux001 ~]# mdadm --create --help        #使用mdadm命令，--help有参考