Linux磁盘-RIAD阵列-软件阵列

#这台服务器，准备了2块多余的磁盘，sdb和sdc，我们使用他来模拟一个RAID1.[root@localhost ~]# lsblkNAME            MAJ:MIN RM  SIZE RO TYPE MOUNTPOINTsda               8:0    0   20G  0 disk ├─sda1            8:1    0    1G  0 part /boot└─sda2            8:2    0   19G  0 part   ├─centos-root 253:0    0   17G  0 lvm  /  └─centos-swap 253:1    0    2G  0 lvm  sdb               8:16   0   20G  0 disk sdc               8:32   0   20G  0 disk sr0              11:0    1  973M  0 rom

yum -y install mdadm

mdadm --create /dev/md0 --level=1 --raid-devices=2 /dev/sdb /dev/sdc --metadata=0.90# /dev/md0 是设备的名字，可根据需要自己定义# --level=1 是阵列的级别# --metadata=0.90 主要是兼容性问题

#可以看到2个磁盘组成了一个阵列磁盘[root@localhost ~]# lsblkNAME            MAJ:MIN RM  SIZE RO TYPE  MOUNTPOINTsda               8:0    0   20G  0 disk  ├─sda1            8:1    0    1G  0 part  /boot└─sda2            8:2    0   19G  0 part    ├─centos-root 253:0    0   17G  0 lvm   /  └─centos-swap 253:1    0    2G  0 lvm   sdb               8:16   0   20G  0 disk  └─md0             9:0    0   20G  0 raid1 sdc               8:32   0   20G  0 disk  └─md0             9:0    0   20G  0 raid1

[root@localhost ~]# ll /dev/md0 brw-rw---- 1 root disk 9, 0 7月  19 22:19 /dev/md0

[root@localhost ~]# fdisk /dev/md0 欢迎使用 fdisk (util-linux 2.23.2)。更改将停留在内存中，直到您决定将更改写入磁盘。使用写入命令前请三思。Device does not contain a recognized partition table使用磁盘标识符 0x92791e84 创建新的 DOS 磁盘标签。命令(输入 m 获取帮助)：命令(输入 m 获取帮助)：m命令操作   a   toggle a bootable flag   b   edit bsd disklabel   c   toggle the dos compatibility flag   d   delete a partition   g   create a new empty GPT partition table   G   create an IRIX (SGI) partition table   l   list known partition types   m   print this menu   n   add a new partition   o   create a new empty DOS partition table   p   print the partition table   q   quit without saving changes   s   create a new empty Sun disklabel   t   change a partition's system id   u   change display/entry units   v   verify the partition table   w   write table to disk and exit   x   extra functionality (experts only)命令(输入 m 获取帮助)：nPartition type:   p   primary (0 primary, 0 extended, 4 free)   e   extendedSelect (default p): Using default response p分区号 (1-4，默认 1)：起始 扇区 (2048-41942911，默认为 2048)：将使用默认值 2048Last 扇区, +扇区 or +size{K,M,G} (2048-41942911，默认为 41942911)：将使用默认值 41942911分区 1 已设置为 Linux 类型，大小设为 20 GiB命令(输入 m 获取帮助)：wThe partition table has been altered!Calling ioctl() to re-read partition table.正在同步磁盘。

#分区名字可以通过lsblk或者直接看/dev里面的设备名字来获取[root@localhost ~]# mkfs.ext4 /dev/md0p1 mke2fs 1.42.9 (28-Dec-2013)文件系统标签=OS type: Linux块大小=4096 (log=2)分块大小=4096 (log=2)Stride=0 blocks, Stripe width=0 blocks1310720 inodes, 5242608 blocks262130 blocks (5.00%) reserved for the super user第一个数据块=0Maximum filesystem blocks=2153775104160 block groups32768 blocks per group, 32768 fragments per group8192 inodes per groupSuperblock backups stored on blocks:     32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,     4096000Allocating group tables: 完成                            正在写入inode表: 完成                            Creating journal (32768 blocks): 完成Writing superblocks and filesystem accounting information: 完成

[root@localhost ~]# mkdir /mnt/raid[root@localhost ~]# mount /dev/md0p1 /mnt/raid[root@localhost ~]# df -h文件系统                 容量  已用  可用 已用% 挂载点devtmpfs                 475M     0  475M    0% /devtmpfs                    487M     0  487M    0% /dev/shmtmpfs                    487M  7.7M  479M    2% /runtmpfs                    487M     0  487M    0% /sys/fs/cgroup/dev/mapper/centos-root   17G  2.1G   15G   12% //dev/sda1               1014M  138M  877M   14% /boottmpfs                     98M     0   98M    0% /run/user/0/dev/md0p1                20G   45M   19G    1% /mnt/raid

#两个磁盘组成的RAID是正常的[root@localhost ~]# mdadm --detail /dev/md0  /dev/md0:           Version : 0.90     Creation Time : Fri Jul 19 22:19:27 2024        Raid Level : raid1        Array Size : 20971456 (20.00 GiB 21.47 GB)     Used Dev Size : 20971456 (20.00 GiB 21.47 GB)      Raid Devices : 2     Total Devices : 2   Preferred Minor : 0       Persistence : Superblock is persistent       Update Time : Fri Jul 19 22:28:19 2024             State : clean     Active Devices : 2   Working Devices : 2    Failed Devices : 0     Spare Devices : 0Consistency Policy : resync              UUID : 0794079f:4ce9add0:bfe78010:bc810f04 (local to host localhost.localdomain)            Events : 0.18    Number   Major   Minor   RaidDevice State       0       8       16        0      active sync   /dev/sdb       1       8       32        1      active sync   /dev/sdc

root@localhost ~]# mdadm --detail /dev/md0  /dev/md0:           Version : 0.90     Creation Time : Fri Jul 19 22:19:27 2024        Raid Level : raid1        Array Size : 20971456 (20.00 GiB 21.47 GB)     Used Dev Size : 20971456 (20.00 GiB 21.47 GB)      Raid Devices : 2     Total Devices : 1   Preferred Minor : 0       Persistence : Superblock is persistent       Update Time : Fri Jul 19 22:31:55 2024             State : clean, degraded     Active Devices : 1   Working Devices : 1    Failed Devices : 0     Spare Devices : 0Consistency Policy : resync              UUID : 0794079f:4ce9add0:bfe78010:bc810f04 (local to host localhost.localdomain)            Events : 0.18    Number   Major   Minor   RaidDevice State       -       0        0        0      removed       1       8       16        1      active sync   /dev/sdb## 可以看到，已经有块盘离线了## 下面我们继续挂载，然后向里面写数据，都是ok的，体现了raid的1高可用性。[root@localhost ~]# mount /dev/md0p1 /mnt/raid[root@localhost ~]# cd /mnt/raid[root@localhost raid]# touch abcd[root@localhost raid]# ll总用量 16-rw-r--r-- 1 root root     0 7月  19 22:34 abcddrwx------ 2 root root 16384 7月  19 22:24 lost+found[root@localhost raid]#