4-构建软RAID磁盘阵列
2016.6.16
案例：构建软RAID磁盘阵列
需求描述
- 为Linux服务器添加4块SCSI硬盘
- 使用mdadm软件包，构建RAID5磁盘阵列，提高磁盘存储的性能和可靠性
步骤
- 安装mdadm
- 准备用于RAID阵列的分区
- 为Linux服务器添加4块SCSI硬盘，并使用fdisk工具个划分出一块2GB的分区依次为：/dev/sde1、/dev/sdg1、/dev/sdh1、/dev/sdf1
- 将其类型ID更改为“fd”,对应为“Linux raid autodetect”,表示支持用于RAID磁盘阵列
- 创建RAID设备
- 在RAID设备中建立文件系统
- 挂载并使用文件系统
增加硬盘、分区（关掉虚拟机的情况下，增加硬盘）
1.增加分区（虚拟机是这样，真机是需要加硬盘）
2.分区以及检验分区信息
3.转换类型以及查看转后的信息
现有磁盘信息：
[root@test2 jason]# fdisk -l
Disk /dev/sdb: 85.9 GB, 85899345920 bytes
255 heads, 63 sectors/track, 10443 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xa8f24694
Device Boot Start End Blocks Id System
/dev/sdb1 1 2612 20980858+ 83 Linux
/dev/sdb2 2613 5224 20980890 8e Linux LVM
/dev/sdb3 5225 10443 41921617+ 83 Linux
Disk /dev/sda: 21.5 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x000d0a36
Device Boot Start End Blocks Id System
/dev/sda1 * 1 64 512000 83 Linux
Partition 1 does not end on cylinder boundary.
/dev/sda2 64 2611 20458496 8e Linux LVM
Disk /dev/sdd: 107.4 GB, 107374182400 bytes
255 heads, 63 sectors/track, 13054 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xef9a8da9
Device Boot Start End Blocks Id System
/dev/sdd1 1 13054 104856223+ 8e Linux LVM
Disk /dev/sde: 21.5 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
Disk /dev/sdc: 85.9 GB, 85899345920 bytes
255 heads, 63 sectors/track, 10443 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x8967e34e
Device Boot Start End Blocks Id System
/dev/sdc1 1 2612 20980858+ 83 Linux
/dev/sdc2 2613 5224 20980890 8e Linux LVM
Disk /dev/sdg: 21.5 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
Disk /dev/sdf: 21.5 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
Disk /dev/sdh: 21.5 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
Disk /dev/mapper/vg_jason-lv_root: 18.8 GB, 18798870528 bytes
255 heads, 63 sectors/track, 2285 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
Disk /dev/mapper/vg_jason-lv_swap: 2147 MB, 2147483648 bytes
255 heads, 63 sectors/track, 261 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
Disk /dev/mapper/mail_store-mbox: 128.8 GB, 128849018880 bytes
255 heads, 63 sectors/track, 15665 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
[root@test2 jason]#
sde1分出2G的主分区，并转换成"fd”（Linux raid autodetect ）：
[root@test2 jason]# fdisk /dev/sde
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel with disk identifier 0xe4b1d138.
Changes will remain in memory only, until you decide to write them.
After that, of course, the previous content won't be recoverable.
Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)
WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
switch off the mode (command 'c') and change display units to
sectors (command 'u').
Command (m for help): n
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4): 1
First cylinder (1-2610, default 1):
Using default value 1
Last cylinder, +cylinders or +size{K,M,G} (1-2610, default 2610): +2G
Command (m for help): t
Selected partition 1
Hex code (type L to list codes): fd
Changed system type of partition 1 to fd (Linux raid autodetect)
Command (m for help): p
Disk /dev/sde: 21.5 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xe4b1d138
Device Boot Start End Blocks Id System
/dev/sde1 1 262 2104483+ fd Linux raid autodetect
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
[root@test2 jason]#
一样的方法来处理sdg
[root@test2 jason]# fdisk /dev/sd
sda sda1 sda2 sdb sdb1 sdb2 sdb3 sdc sdc1 sdc2 sdd sdd1 sde sde1 sdf sdg sdh
[root@test2 jason]# fdisk /dev/sdg
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel with disk identifier 0x37970afa.
Changes will remain in memory only, until you decide to write them.
After that, of course, the previous content won't be recoverable.
Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)
WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
switch off the mode (command 'c') and change display units to
sectors (command 'u').
Command (m for help): n
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4): 1
First cylinder (1-2610, default 1):
Using default value 1
Last cylinder, +cylinders or +size{K,M,G} (1-2610, default 2610): +2G
Command (m for help): t
Selected partition 1
Hex code (type L to list codes): fd
Changed system type of partition 1 to fd (Linux raid autodetect)
Command (m for help): p
Disk /dev/sdg: 21.5 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x37970afa
Device Boot Start End Blocks Id System
/dev/sdg1 1 262 2104483+ fd Linux raid autodetect
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
sdf:
[root@test2 jason]# fdisk /dev/sd
sda sda2 sdb1 sdb3 sdc1 sdd sde sdf sdg1
sda1 sdb sdb2 sdc sdc2 sdd1 sde1 sdg sdh
[root@test2 jason]# fdisk /dev/sdf
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel with disk identifier 0x65c9c4f1.
Changes will remain in memory only, until you decide to write them.
After that, of course, the previous content won't be recoverable.
Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)
WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
switch off the mode (command 'c') and change display units to
sectors (command 'u').
Command (m for help): n
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4): 1
First cylinder (1-2610, default 1):
Using default value 1
Last cylinder, +cylinders or +size{K,M,G} (1-2610, default 2610): +2g
Unsupported suffix: 'g'.
Supported: 10^N: KB (KiloByte), MB (MegaByte), GB (GigaByte)
2^N: K (KibiByte), M (MebiByte), G (GibiByte)
Last cylinder, +cylinders or +size{K,M,G} (1-2610, default 2610): +2G
Command (m for help): t
Selected partition 1
Hex code (type L to list codes): fd
Changed system type of partition 1 to fd (Linux raid autodetect)
Command (m for help): p
Disk /dev/sdf: 21.5 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x65c9c4f1
Device Boot Start End Blocks Id System
/dev/sdf1 1 262 2104483+ fd Linux raid autodetect
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
sdh
[root@test2 jason]# fdisk /dev/sd
sda sda2 sdb1 sdb3 sdc1 sdd sde sdf sdg sdh
sda1 sdb sdb2 sdc sdc2 sdd1 sde1 sdf1 sdg1
[root@test2 jason]# fdisk /dev/sdh
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel with disk identifier 0xdeb9d0d0.
Changes will remain in memory only, until you decide to write them.
After that, of course, the previous content won't be recoverable.
Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)
WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
switch off the mode (command 'c') and change display units to
sectors (command 'u').
Command (m for help): n
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4): 1
First cylinder (1-2610, default 1):
Using default value 1
Last cylinder, +cylinders or +size{K,M,G} (1-2610, default 2610): +2G
Command (m for help): t
Selected partition 1
Hex code (type L to list codes): fd
Changed system type of partition 1 to fd (Linux raid autodetect)
Command (m for help): p
Disk /dev/sdh: 21.5 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xdeb9d0d0
Device Boot Start End Blocks Id System
/dev/sdh1 1 262 2104483+ fd Linux raid autodetect
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
[root@test2 jason]#
探测刚刚的分区是否被电脑识别：
[root@test2 jason]# partprobe /dev/sde
sde sde1
[root@test2 jason]# partprobe /dev/sdg
sdg sdg1
[root@test2 jason]# partprobe /dev/sdh
sdh sdh1
[root@test2 jason]# partprobe /dev/sdf
sdf sdf1
再次查看分区信息：
[root@test2 jason]# fdisk -l | grep "/dev"
Disk /dev/sdb: 85.9 GB, 85899345920 bytes
/dev/sdb1 1 2612 20980858+ 83 Linux
/dev/sdb2 2613 5224 20980890 8e Linux LVM
/dev/sdb3 5225 10443 41921617+ 83 Linux
Disk /dev/sda: 21.5 GB, 21474836480 bytes
/dev/sda1 * 1 64 512000 83 Linux
/dev/sda2 64 2611 20458496 8e Linux LVM
Disk /dev/sdd: 107.4 GB, 107374182400 bytes
/dev/sdd1 1 13054 104856223+ 8e Linux LVM
Disk /dev/sde: 21.5 GB, 21474836480 bytes
/dev/sde1 1 262 2104483+ fd Linux raid autodetect
Disk /dev/sdc: 85.9 GB, 85899345920 bytes
/dev/sdc1 1 2612 20980858+ 83 Linux
/dev/sdc2 2613 5224 20980890 8e Linux LVM
Disk /dev/sdg: 21.5 GB, 21474836480 bytes
/dev/sdg1 1 262 2104483+ fd Linux raid autodetect
Disk /dev/sdf: 21.5 GB, 21474836480 bytes
/dev/sdf1 1 262 2104483+ fd Linux raid autodetect
Disk /dev/sdh: 21.5 GB, 21474836480 bytes
/dev/sdh1 1 262 2104483+ fd Linux raid autodetect
Disk /dev/mapper/vg_jason-lv_root: 18.8 GB, 18798870528 bytes
Disk /dev/mapper/vg_jason-lv_swap: 2147 MB, 2147483648 bytes
Disk /dev/mapper/mail_store-mbox: 128.8 GB, 128849018880 bytes
[root@test2 jason]#
1.创建
2.查看
- ls -l /dev/md0
- cat /proc/mdstat
创建阵列
[root@test2 jason]# mdadm -Cv /dev/md0 -a yes -n4 -l5 /dev/sde1 /dev/sdg1 /dev/sdh1 /dev/sdf1
mdadm: layout defaults to left-symmetric
mdadm: layout defaults to left-symmetric
mdadm: chunk size defaults to 512K
mdadm: size set to 2102272K
mdadm: Defaulting to version 1.2 metadata
mdadm: array /dev/md0 started.
[root@test2 jason]#
- -a：就是如果有需要创建的，就直接创建，比如说md0这个之前是不存在的目录，那么在创建阵列的同时直接创建md0
- md0：一般讲RAID命名成md0
- -n：几块硬盘，就写几
- -l：级别，或者说类型，5，就是RAID5
- 后面跟着的是把具体某个硬盘的某个分区创建成RAID
- -C：是创建阵列
另一种方法：
- --create：创建这列
- --auto=yes
- --raid-devices=4
- --level=5
- --spare-devices
创建后的查看：
[root@test2 jason]# ls -l /dev/md0
brw-rw---- 1 root disk 9, 0 Jun 16 16:11 /dev/md0
[root@test2 jason]#
另一种查看方式：
[root@test2 jason]# cat /proc/mdstat
Personalities : [raid6] [raid5] [raid4]
md0 : active raid5 sdf1[4] sdh1[2] sdg1[1] sde1[0]
6306816 blocks super 1.2 level 5, 512k chunk, algorithm 2 [4/4] [UUUU]
unused devices: <none>
[root@test2 jason]#
- [4/4]：第一个4是代表4个分区，第二个4表示正常工作的有几个
- [UUUU]：表示up，正常启动的有几个，如果有一个有问题，那么会用“_”（下划线）来表示。
- 上面sdf1[4]代表的是最后一个U
- sde1[0]代表是第一个U
- sdg1[1]则是第二个
- sdh1[2]是第三个
1.查看格式化前的信息
2.格式化
3.检验格式化的结果
格式化：
[root@test2 jason]# mkfs -t ext4 /dev/md0
mke2fs 1.41.12 (17-May-2010)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=128 blocks, Stripe width=384 blocks
394352 inodes, 1576704 blocks
78835 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=1614807040
49 block groups
32768 blocks per group, 32768 fragments per group
8048 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done
This filesystem will be automatically checked every 25 mounts or
180 days, whichever comes first. Use tune2fs -c or -i to override.
[root@test2 jason]#
挂载
1.检查挂载前的信息
2.明确挂载目录（如果已经存在可以直接挂载，如果不存在就需要自己挂载）
3.挂载方式
* 一次性挂载
* 开机后自动挂载
4.检验挂载行为的结果
* mount
* df -hT
创建mdata目录在根下面，作为挂载点：
[root@test2 jason]# mkdir /mdata
挂载/dev/md0：
[root@test2 jason]# mount /dev/md0 /mdata
查看挂载信息的方式：
[root@test2 jason]# mount
/dev/mapper/vg_jason-lv_root on / type ext4 (rw)
proc on /proc type proc (rw)
sysfs on /sys type sysfs (rw)
devpts on /dev/pts type devpts (rw,gid=5,mode=620)
tmpfs on /dev/shm type tmpfs (rw)
/dev/sda1 on /boot type ext4 (rw)
/dev/sdc1 on /home type ext4 (rw)
none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw)
vmware-vmblock on /var/run/vmblock-fuse type fuse.vmware-vmblock (rw,nosuid,nodev,default_permissions,allow_other)
gvfs-fuse-daemon on /root/.gvfs type fuse.gvfs-fuse-daemon (rw,nosuid,nodev)
/dev/sr0 on /media/CentOS_6.5_Final type iso9660 (ro,nosuid,nodev,uhelper=udisks,uid=0,gid=0,iocharset=utf8,mode=0400,dmode=0500)
/dev/md0 on /mdata type ext4 (rw)
另一种查看挂载信息的方式：
[root@test2 jason]# df -hT
Filesystem Type Size Used Avail Use% Mounted on
/dev/mapper/vg_jason-lv_root ext4 18G 4.3G 13G 27% /
tmpfs tmpfs 3.9G 76K 3.9G 1% /dev/shm
/dev/sda1 ext4 485M 40M 421M 9% /boot
/dev/sdc1 ext4 20G 422M 19G 3% /home
/dev/sr0 iso9660 4.2G 4.2G 0 100% /media/CentOS_6.5_Final
/dev/md0 ext4 6.0G 141M 5.5G 3% /mdata
[root@test2 jason]#
因为是RAID 5，有一块盘是用来做校验的，所以实际的容量是6G。
修改fstab配置文件，达到开机后自动挂载的目的。
1.备份fstab
2.修改
3.测试修改的效果
- 卸载
- 重新挂载
- 查看挂载信息
先备份一下fstab文件
[root@test2 jason]# cp /etc/fstab /etc/fstab.bak
更改配置文件，以便于重启之后可以自动挂载
[root@test2 jason]# vim /etc/fstab
#
# /etc/fstab
# Created by anaconda on Wed May 18 04:04:40 2016
#
# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
/dev/mapper/vg_jason-lv_root / ext4 defaults 1 1
UUID=12a13375-c595-4876-9fc2-3158f535861d /boot ext4 defaults 1 2
/dev/mapper/vg_jason-lv_swap swap swap defaults 0 0
tmpfs /dev/shm tmpfs defaults 0 0
devpts /dev/pts devpts gid=5,mode=620 0 0
sysfs /sys sysfs defaults 0 0
proc /proc proc defaults 0 0
/dev/sdc1 /home ext4 defaults 0 0
/dev/md0 /mdata ext4 defaults 0 0
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:wq
测试是否奏效： 先卸载并查看挂载信息：
[root@test2 jason]# umount /mdata/
[root@test2 jason]# df -hT
Filesystem Type Size Used Avail Use% Mounted on
/dev/mapper/vg_jason-lv_root ext4 18G 4.3G 13G 27% /
tmpfs tmpfs 3.9G 76K 3.9G 1% /dev/shm
/dev/sda1 ext4 485M 40M 421M 9% /boot
/dev/sdc1 ext4 20G 422M 19G 3% /home
/dev/sr0 iso9660 4.2G 4.2G 0 100% /media/CentOS_6.5_Final
[root@test2 jason]#
挂载，并查看信息：
[root@test2 jason]# mount -a [root@test2 jason]# df -hT Filesystem Type Size Used Avail Use% Mounted on /dev/mapper/vg_jason-lv_root ext4 18G 4.3G 13G 27% / tmpfs tmpfs 3.9G 76K 3.9G 1% /dev/shm /dev/sda1 ext4 485M 40M 421M 9% /boot /dev/sdc1 ext4 20G 422M 19G 3% /home /dev/sr0 iso9660 4.2G 4.2G 0 100% /media/CentOS_6.5_Final /dev/md0 ext4 6.0G 141M 5.5G 3% /mdata [root@test2 jason]#
RAID阵列的管理及设备恢复
- 扫描或查看磁盘阵列信息
- 启动/停止RAID阵列
- 设备恢复操作
- 模拟阵列设备故障
- 更换故障设备，并恢复数据
查看磁盘阵列信息
注意参数这里面是在意顺序的：
[root@test2 jason]# mdadm -sDv
mdadm: -s does not set the mode, and so cannot be the first option.
合适的顺序：
[root@test2 jason]# mdadm -vDs
ARRAY /dev/md0 level=raid5 num-devices=4 metadata=1.2 name=test2:0 UUID=10a00bcf:d67ab596:18b5fa25:8ef335e1
devices=/dev/sde1,/dev/sdg1,/dev/sdh1,/dev/sdf1
[root@test2 jason]#
另一种查看方式：
[root@test2 jason]# mdadm -vDs /dev/md0
/dev/md0:
Version : 1.2
Creation Time : Thu Jun 16 16:11:19 2016
Raid Level : raid5
Array Size : 6306816 (6.01 GiB 6.46 GB)
Used Dev Size : 2102272 (2.00 GiB 2.15 GB)
Raid Devices : 4
Total Devices : 4
Persistence : Superblock is persistent
Update Time : Thu Jun 16 16:43:12 2016
State : clean
Active Devices : 4
Working Devices : 4
Failed Devices : 0
Spare Devices : 0
Layout : left-symmetric
Chunk Size : 512K
Name : test2:0 (local to host test2)
UUID : 10a00bcf:d67ab596:18b5fa25:8ef335e1
Events : 18
Number Major Minor RaidDevice State
0 8 65 0 active sync /dev/sde1
1 8 97 1 active sync /dev/sdg1
2 8 113 2 active sync /dev/sdh1
4 8 81 3 active sync /dev/sdf1
[root@test2 jason]#
自己创建mdadm.conf文件的方法和格式：
[root@test2 jason]# mdadm -vDs > /etc/mdadm.conf
[root@test2 jason]# vi /etc/mdadm.conf
DEVICE /dev/sde1 /dev/sdg1 /dev/sdh1 /dev/sdf1ARRAY /dev/md0 level=raid5 num-devices=4 UUID=10a00bcf:d67ab596:18b5fa25:8ef335e1
devices=/dev/sde1,/dev/sdg1,/dev/sdh1,/dev/sdf1
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:wq
通过停止和启动/dev/md0来测试配置文件是否生效： 直接停止：
[root@test2 jason]# mdadm -S /dev/md0
mdadm: Cannot get exclusive access to /dev/md0:Perhaps a running process, mounted filesystem or active volume group?
[root@test2 jason]#
提示是正在运行的进程
卸载：
[root@test2 jason]# umount /dev/md0
停止：
[root@test2 jason]# mdadm -S /dev/md0
mdadm: stopped /dev/md0
[root@test2 jason]# df -hT
Filesystem Type Size Used Avail Use% Mounted on
/dev/mapper/vg_jason-lv_root ext4 18G 4.3G 13G 27% /
tmpfs tmpfs 3.9G 76K 3.9G 1% /dev/shm
/dev/sda1 ext4 485M 40M 421M 9% /boot
/dev/sdc1 ext4 20G 422M 19G 3% /home
/dev/sr0 iso9660 4.2G 4.2G 0 100% /media/CentOS_6.5_Final
启动：
[root@test2 jason]# mdadm -A /dev/md0
mdadm: /dev/md0 has been started with 4 drives.
证明配置文件是正确的
启动不等于挂载
[root@test2 jason]# df -hT
Filesystem Type Size Used Avail Use% Mounted on
/dev/mapper/vg_jason-lv_root ext4 18G 4.3G 13G 27% /
tmpfs tmpfs 3.9G 76K 3.9G 1% /dev/shm
/dev/sda1 ext4 485M 40M 421M 9% /boot
/dev/sdc1 ext4 20G 422M 19G 3% /home
/dev/sr0 iso9660 4.2G 4.2G 0 100% /media/CentOS_6.5_Final
[root@test2 jason]#
重新挂载：
[root@test2 jason]# mount -a
[root@test2 jason]# mount
/dev/mapper/vg_jason-lv_root on / type ext4 (rw)
proc on /proc type proc (rw)
sysfs on /sys type sysfs (rw)
devpts on /dev/pts type devpts (rw,gid=5,mode=620)
tmpfs on /dev/shm type tmpfs (rw)
/dev/sda1 on /boot type ext4 (rw)
/dev/sdc1 on /home type ext4 (rw)
none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw)
vmware-vmblock on /var/run/vmblock-fuse type fuse.vmware-vmblock (rw,nosuid,nodev,default_permissions,allow_other)
gvfs-fuse-daemon on /root/.gvfs type fuse.gvfs-fuse-daemon (rw,nosuid,nodev)
/dev/sr0 on /media/CentOS_6.5_Final type iso9660 (ro,nosuid,nodev,uhelper=udisks,uid=0,gid=0,iocharset=utf8,mode=0400,dmode=0500)
/dev/md0 on /mdata type ext4 (rw)
[root@test2 jason]#
移除一块硬盘
1.查看移除前的状态
2.移除
* 设定为faulty状态
* 移除操作
3.检查移除后的状态
现在模拟，假设sde1坏掉，然后把sde1移除：
第一步将sde1设定为"faulty"状态：
[root@test2 jason]# mdadm /dev/md0 -f /dev/sde1
mdadm: set /dev/sde1 faulty in /dev/md0
查看mdstat
[root@test2 jason]# cat /proc/mdstat
Personalities : [raid6] [raid5] [raid4]
md0 : active raid5 sde1[0](F) sdf1[4] sdh1[2] sdg1[1]
6306816 blocks super 1.2 level 5, 512k chunk, algorithm 2 [4/3] [_UUU]
unused devices: <none>
第二部移除坏掉的sde1：
[root@test2 jason]# mdadm /dev/md0 -r /dev/sde1
mdadm: hot removed /dev/sde1 from /dev/md0
查看remove后的信息：
[root@test2 jason]# cat /proc/mdstat
Personalities : [raid6] [raid5] [raid4]
md0 : active raid5 sdf1[4] sdh1[2] sdg1[1]
6306816 blocks super 1.2 level 5, 512k chunk, algorithm 2 [4/3] [_UUU]
unused devices: <none>
[root@test2 jason]#
增加一块硬盘
1.检查增加前的状态
2.增加
3.检查增加后的状态。
现在假定sde1是正常的盘，再把sde1加进md0当中：
[root@test2 jason]# mdadm /dev/md0 -a /dev/sde1
mdadm: added /dev/sde1
使用/proc/mdstat来查看加入的进度：
[root@test2 jason]# cat /proc/mdstat
Personalities : [raid6] [raid5] [raid4]
md0 : active raid5 sde1[5] sdf1[4] sdh1[2] sdg1[1]
6306816 blocks super 1.2 level 5, 512k chunk, algorithm 2 [4/3] [_UUU]
[======>..............] recovery = 33.6% (706560/2102272) finish=0.0min speed=235520K/sec
unused devices: <none>
[root@test2 jason]# cat /proc/mdstat
Personalities : [raid6] [raid5] [raid4]
md0 : active raid5 sde1[5] sdf1[4] sdh1[2] sdg1[1]
6306816 blocks super 1.2 level 5, 512k chunk, algorithm 2 [4/3] [_UUU]
[===========>.........] recovery = 56.2% (1182388/2102272) finish=0.0min speed=236477K/sec
unused devices: <none>
[root@test2 jason]# cat /proc/mdstat
Personalities : [raid6] [raid5] [raid4]
md0 : active raid5 sde1[5] sdf1[4] sdh1[2] sdg1[1]
6306816 blocks super 1.2 level 5, 512k chunk, algorithm 2 [4/3] [_UUU]
[=============>.......] recovery = 66.5% (1400064/2102272) finish=0.0min speed=200009K/sec
unused devices: <none>
[root@test2 jason]# cat /proc/mdstat
Personalities : [raid6] [raid5] [raid4]
md0 : active raid5 sde1[5] sdf1[4] sdh1[2] sdg1[1]
6306816 blocks super 1.2 level 5, 512k chunk, algorithm 2 [4/3] [_UUU]
[=================>...] recovery = 85.5% (1800064/2102272) finish=0.0min speed=225008K/sec
unused devices: <none>
[root@test2 jason]# cat /proc/mdstat
Personalities : [raid6] [raid5] [raid4]
md0 : active raid5 sde1[5] sdf1[4] sdh1[2] sdg1[1]
6306816 blocks super 1.2 level 5, 512k chunk, algorithm 2 [4/3] [_UUU]
[==================>..] recovery = 92.0% (1936640/2102272) finish=0.0min speed=215182K/sec
unused devices: <none>
加入完成：
[root@test2 jason]# cat /proc/mdstat
Personalities : [raid6] [raid5] [raid4]
md0 : active raid5 sde1[5] sdf1[4] sdh1[2] sdg1[1]
6306816 blocks super 1.2 level 5, 512k chunk, algorithm 2 [4/4] [UUUU]
unused devices: <none>
[root@test2 jason]# cat /proc/mdstat
Personalities : [raid6] [raid5] [raid4]
md0 : active raid5 sde1[5] sdf1[4] sdh1[2] sdg1[1]
6306816 blocks super 1.2 level 5, 512k chunk, algorithm 2 [4/4] [UUUU]
unused devices: <none>
[root@test2 jason]#