*由四个分区组成raid 5
*每个分区1G，每个分区最好一样大
*利用一个分区设为sparedisk
*sparedisk与其它raid分区一样大
*将此raid 5 设备挂载待/mnt/raid目录下
1.分区
[root@server3 mnt]# fdisk /dev/vdb
Welcome to fdisk (util-linux 2.23.2).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.
Command (m for help): n
Partition type:
p primary (0 primary, 0 extended, 4 free)
e extended
Select (default p): p
Partition number (1-4, default 1):
First sector (2048-41943039, default 2048):
Using default value 2048
Last sector, +sectors or +size{K,M,G} (2048-41943039, default 41943039): +1G
Partition 1 of type Linux and of size 1 GiB is set
Command (m for help): p
Disk /dev/vdb: 21.5 GB, 21474836480 bytes, 41943040 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x7afa732b
Device Boot Start End Blocks Id System
/dev/vdb1 2048 2099199 1048576 83 Linux
/dev/vdb2 2099200 4196351 1048576 83 Linux
/dev/vdb3 4196352 6293503 1048576 83 Linux
/dev/vdb4 6293504 41943039 17824768 5 Extended
/dev/vdb5 6295552 8392703 1048576 83 Linux
/dev/vdb6 8394752 10491903 1048576 83 Linux
[root@server3 ~]# partprobe **可能会出现报错，重启就好
2.以mdadm创建RAID
[root@server3 ~]# mdadm --create --auto=yes /dev/md0 --level=5 --raid-devices=4 --spare-devices=1 /dev/vdb{2,3,5,6,7} <==个人问题，自己由新分了个区
mdadm: Defaulting to version 1.2 metadata
mdadm: array /dev/md0 started.
[root@server3 ~]# mdadm --detail /dev/md0
/dev/md0: <==RAID设备文件名
Version : 1.2
Creation Time : Mon Jan 21 15:41:42 2019 <==被创建时间
Raid Level : raid5 <==RAID等级
Array Size : 3142656 (3.00 GiB 3.22 GB) <==raid可用磁盘量
Used Dev Size : 1047552 (1023.00 MiB 1072.69 MB) <==每个设备的可用量
Raid Devices : 4 <==用作RAID的设备数量
Total Devices : 5 <==全部设备数量
Persistence : Superblock is persistent
Update Time : Mon Jan 21 15:41:52 2019
State : clean, degraded, recovering
Active Devices : 4 <==启动的设备数量
Working Devices : 5 <==可动作的设备数量
Failed Devices : 0 <==出现错误的设备数量
Spare Devices : 1 <==预备磁盘数量
Layout : left-symmetric
Chunk Size : 512K
Rebuild Status : 12% complete
Name : server3:0 (local to host server3)
UUID : 4c7f9840:5a192f12:004c417e:29d8c02e
Events : 2
Number Major Minor RaidDevice State
0 253 18 0 active sync /dev/vdb2
1 253 19 1 active sync /dev/vdb3
2 253 21 2 active sync /dev/vdb5
5 253 22 3 spare rebuilding /dev/vdb6
4 253 23 - spare /dev/vdb7
3.磁盘阵列的情况也可用下面这个文件查看
[root@server3 ~]# cat /proc/mdstat
Personalities : [raid6] [raid5] [raid4]
md0 : active raid5 vdb6[5] vdb7[4](S) vdb5[2] vdb3[1] vdb2[0]
3142656 blocks super 1.2 level 5, 512k chunk, algorithm 2 [4/4] [UUUU]
unused devices: <none>
格式化与挂载使用RAID
[root@server3 ~]# 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=384 blocks
196608 inodes, 785664 blocks
39283 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=805306368
24 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912
Allocating group tables: done
Writing inode tables: done
Creating journal (16384 blocks): done
Writing superblocks and filesystem accounting information: done
[root@server3 ~]# cd /mnt/
[root@server3 mnt]# ls raid/ <==自行创建
[root@server3 mnt]# mount /dev/md0 raid/
[root@server3 mnt]# df
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/vda3 20243456 3441540 16801916 18% /
devtmpfs 493580 0 493580 0% /dev
tmpfs 508248 84 508164 1% /dev/shm
tmpfs 508248 13564 494684 3% /run
tmpfs 508248 0 508248 0% /sys/fs/cgroup
/dev/vda1 201380 133424 67956 67% /boot
tmpfs 101652 20 101632 1% /run/user/42
tmpfs 101652 0 101652 0% /run/user/0
/dev/md0 3027728 9216 2844996 1% /mnt/raid
4.错误救援模式
首先设置磁盘为错误
[root@server3 mnt]# cp -a /var/log raid/ *复制一些东西到/mnt/raid中去
[root@server3 mnt]# df /mnt/raid/ ; du -sm /mnt/raid/
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/md0 3027728 15404 2838808 1% /mnt/raid
7 /mnt/raid/
假设/dev/vdb5出错了
[root@server3 mnt]# mdadm --manage /dev/md0 --fail /dev/vdb5
mdadm: set /dev/vdb5 faulty in /dev/md0
[root@server3 mnt]# mdadm --detail /dev/md0
/dev/md0:
Version : 1.2
Creation Time : Mon Jan 21 15:41:42 2019
Raid Level : raid5
Array Size : 3142656 (3.00 GiB 3.22 GB)
Used Dev Size : 1047552 (1023.00 MiB 1072.69 MB)
Raid Devices : 4
Total Devices : 5
Persistence : Superblock is persistent
Update Time : Mon Jan 21 16:18:46 2019
State : clean, degraded, recovering
Active Devices : 3
Working Devices : 4
Failed Devices : 1
Spare Devices : 1
Layout : left-symmetric
Chunk Size : 512K
Rebuild Status : 11% complete
Name : server3:0 (local to host server3)
UUID : 4c7f9840:5a192f12:004c417e:29d8c02e
Events : 21
Number Major Minor RaidDevice State
0 253 18 0 active sync /dev/vdb2
1 253 19 1 active sync /dev/vdb3
4 253 23 2 spare rebuilding /dev/vdb7
5 253 22 3 active sync /dev/vdb6
2 253 21 - faulty /dev/vdb5
[root@server3 mnt]# mdadm --manage /dev/md0 --fail /dev/vdb5
mdadm: set /dev/vdb5 faulty in /dev/md0
[root@server3 mnt]# mdadm --detail /dev/md0
/dev/md0:
Version : 1.2
Creation Time : Mon Jan 21 15:41:42 2019
Raid Level : raid5
Array Size : 3142656 (3.00 GiB 3.22 GB)
Used Dev Size : 1047552 (1023.00 MiB 1072.69 MB)
Raid Devices : 4
Total Devices : 5
Persistence : Superblock is persistent
Update Time : Mon Jan 21 16:18:46 2019
State : clean, degraded, recovering
Active Devices : 3
Working Devices : 4
Failed Devices : 1 **有一个出错了
Spare Devices : 1
Layout : left-symmetric
Chunk Size : 512K
Rebuild Status : 11% complete
Name : server3:0 (local to host server3)
UUID : 4c7f9840:5a192f12:004c417e:29d8c02e
Events : 21
Number Major Minor RaidDevice State
0 253 18 0 active sync /dev/vdb2
1 253 19 1 active sync /dev/vdb3
4 253 23 2 spare rebuilding /dev/vdb7
5 253 22 3 active sync /dev/vdb6
2 253 21 - faulty /dev/vdb5
5.将出错的磁盘删除并加入新磁盘
建立新的分区
[root@server3 mnt]# fdisk /dev/vdb
Welcome to fdisk (util-linux 2.23.2).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.
Command (m for help): n
All primary partitions are in use
Adding logical partition 8
First sector (12593152-41943039, default 12593152):
Using default value 12593152
Last sector, +sectors or +size{K,M,G} (12593152-41943039, default 41943039): +1G
Partition 8 of type Linux and of size 1 GiB is set
Command (m for help): wq
The partition table has been altered!
Calling ioctl() to re-read partition table.
WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
The kernel still uses the old table. The new table will be used at
the next reboot or after you run partprobe(8) or kpartx(8)
Syncing disks.
[root@server3 mnt]# partprobe
加入新的磁盘拔除由问题的磁盘
[root@server3 mnt]# mdadm --manage /dev/md0 --add /dev/vdb8 --remove /dev/vdb5
mdadm: added /dev/vdb8
mdadm: hot removed /dev/vdb5 from /dev/md0
[root@server3 mnt]# mdadm --detail /dev/md0
/dev/md0:
Version : 1.2
Creation Time : Mon Jan 21 15:41:42 2019
Raid Level : raid5
Array Size : 3142656 (3.00 GiB 3.22 GB)
Used Dev Size : 1047552 (1023.00 MiB 1072.69 MB)
Raid Devices : 4
Total Devices : 5
Persistence : Superblock is persistent
Update Time : Mon Jan 21 16:26:07 2019
State : clean
Active Devices : 4
Working Devices : 5
Failed Devices : 0
Spare Devices : 1
Layout : left-symmetric
Chunk Size : 512K
Name : server3:0 (local to host server3)
UUID : 4c7f9840:5a192f12:004c417e:29d8c02e
Events : 38
Number Major Minor RaidDevice State
0 253 18 0 active sync /dev/vdb2
1 253 19 1 active sync /dev/vdb3
4 253 23 2 active sync /dev/vdb7
5 253 22 3 active sync /dev/vdb6
6 253 24 - spare /dev/vdb8
6.开机自动启动raid并自动挂载
[root@server3 mnt]# vim /etc/fstab
/dev/md0 /mnt/raid ext4 defaults 1 2
[root@server3 mnt]# mount -a *检测一下是否有问题
7.关闭软件raid
[root@server3 mnt]# umount /dev/md0
[root@server3 mnt]# vim /etc/fstab *删除刚刚写入的那一行
[root@server3 mnt]# mdadm --stop /dev/md0
mdadm: stopped /dev/md0
unused devices: <none>
[root@server3 mnt]# cat /proc/mdstat
Personalities : [raid6] [raid5] [raid4]
unused devices: <none> **不存在任何数据设备