解析linux中raid和lvm

时间:2014-09-24 20:25 来源:linux.it.net.cn 作者:it

raid(磁盘阵列)分为软、硬二种：
软raid
硬raid

raid 0 1 5 10
raid0 :
优点：读写速度加快
缺点：不安全

raid1:
优点：读取速度快，安全
缺点：写入速度慢

raid10:radi1和raid0的集合

raid5:
优点和缺点介于0和1之间

准备4个新分区：

复制代码代码示例:

	[root@station230 ~]# mdadm  --create  /dev/md0  --level=5 --raid-devices=3 --spare-devices=1  /dev/sda{7,8,9,10}

	 

或者：

复制代码代码示例:

	[root@station230 md0]# mdadm -C /dev/md0 -l 5 -n 3 -x 1 /dev/sda{7,8,9,10}

	[root@station230 md0]# mdadm -D /dev/md0

	[root@station230 md0]# mdadm -Ds 

	[root@station230 md0]# mkfs.ext3 /dev/md0

	[root@station230 ~]# mkdir /mnt/md0

	[root@station230 ~]# mount /dev/md0  /mnt/md0

	[root@station230 ~]# cd /mnt/md0

	[root@station230 md0]# ls

	lost+found

主设备号
次设备号

创建设备文件：

复制代码代码示例:

mknod

/proc/devices

[root@station230 dev]# mdadm -Ds > /etc/mdadm.conf
[root@station230 dev]# echo 'mount /dev/md0 /mnt/md0' >> /etc/rc.local
[root@station230 dev]# vim /etc/fstab
/dev/md0 /mnt/md0 ext3 defaults 0 0

[root@station230 dev]# mdadm -D /dev/md0
Number   Major   Minor   RaidDevice State
       0       8        7        0      active sync   /dev/sda7
       1       8       10        1      active sync   /dev/sda10
       2       8        9        2      active sync   /dev/sda9
       3       8        8        -      faulty spare   /dev/sda8

[root@station230 dev]# mdadm -f /dev/md0 /dev/sda8
mdadm: set /dev/sda8 faulty in /dev/md0

[root@station230 dev]# mdadm -r /dev/md0 /dev/sda8
mdadm: hot removed /dev/sda8
[root@station230 dev]# mdadm -a /dev/md0 /dev/sda8
mdadm: added /dev/sda8

lvm（逻辑卷）

创建4个分区：
创建Pv:

复制代码代码示例:

	[root@station230 ~]# pvcreate /dev/sda{11,12,13,14}

	  Physical volume "/dev/sda11" successfully created

	  Physical volume "/dev/sda12" successfully created

	  Physical volume "/dev/sda13" successfully created

	  Physical volume "/dev/sda14" successfully created

创建并加入卷组：

复制代码代码示例:

	[root@station230 ~]# vgcreate vg0 /dev/sda{11,12,13}

	  Volume group "vg0" successfully created

创建lv：

复制代码代码示例:

	[root@station230 dev]# lvcreate -L 70M -n lv0  vg0

	  Rounding up size to full physical extent 72.00 MB

	  Logical volume "lv0" created

创建文件系统：

复制代码代码示例:

[root@station230 dev]# mkdir /mnt/lv0
[root@station230 dev]# mkfs.ext3 /dev/vg0/lv0

[root@station230 dev]# mount /dev/vg0/lv0 /mnt/lv0
[root@station230 dev]# cd /mnt/lv0
[root@station230 lv0]# ls
lost+found

查看：

复制代码代码示例:

[root@station230 lv0]# pvdisplay
[root@station230 lv0]# pvscan

[root@station230 lv0]# vgdisplay
[root@station230 lv0]# vgscan

[root@station230 lv0]# lvdisplay
[root@station230 lv0]# lvscan

扩容：
扩大vg：

复制代码代码示例:

	[root@station230 lv0]# vgextend vg0 /dev/sda14

	  Volume group "vg0" successfully extended

扩大lv：

复制代码代码示例:

	[root@station230 lv0]# lvextend -L 100M /dev/vg0/lv0 

	  Extending logical volume lv0 to 100.00 MB

	  Logical volume lv0 successfully resized

或者：

复制代码代码示例:

[root@station230 lv0]# lvextend -L +30M /dev/vg0/lv0

[root@station230 lv0]# resize2fs /dev/vg0/lv0 100M
resize2fs 1.39 (29-May-2006)
Filesystem at /dev/vg0/lv0 is mounted on /mnt/lv0; on-line resizing required
Performing an on-line resize of /dev/vg0/lv0 to 102400 (1k) blocks.
The filesystem on /dev/vg0/lv0 is now 102400 blocks long.

lvm缩容：
卸载：

复制代码代码示例:

[root@station230 ~]# umount /dev/vg0/lv0

检查文件系统：

复制代码代码示例:

	[root@station230 ~]# e2fsck -f  /dev/vg0/lv0 

	e2fsck 1.39 (29-May-2006)

	Pass 1: Checking inodes, blocks, and sizes

	Pass 2: Checking directory structure

	Pass 3: Checking directory connectivity

	Pass 4: Checking reference counts

	Pass 5: Checking group summary information

	/dev/vg0/lv0: 11/26624 files (9.1% non-contiguous), 9031/102400 blocks

文件系统级别缩容：

复制代码代码示例:

	[root@station230 ~]# resize2fs /dev/vg0/lv0 80M

	resize2fs 1.39 (29-May-2006)

	Resizing the filesystem on /dev/vg0/lv0 to 81920 (1k) blocks.

	The filesystem on /dev/vg0/lv0 is now 81920 blocks long.

lv缩容：

复制代码代码示例:

[root@station230 ~]# lvreduce -L -20M /dev/vg0/lv0
WARNING: Reducing active logical volume to 80.00 MB
THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce lv0? [y/n]: y
Reducing logical volume lv0 to 80.00 MB
Logical volume lv0 successfully resized

[root@station230 ~]# vgreduce vg0 /dev/sda14
Removed "/dev/sda14" from volume group "vg0"

[root@station230 ~]# pvremove /dev/sda14
Labels on physical volume "/dev/sda14" successfully wiped

[root@station230 ~]# vgremove vg0
[root@station230 ~]# lvremove lv0

lvm快照：

复制代码代码示例:

[root@station230 lv0]# lvcreate -s /dev/vg0/lv0 -n lv0bak -L 20M
Logical volume "lv0bak" created

[root@station230 lv0bak]# lvscan
ACTIVE Original '/dev/vg0/lv0' [80.00 MB] inherit
ACTIVE Snapshot '/dev/vg0/lv0bak' [20.00 MB] inherit

替换物理卷：
把新的pv添加到vg：

复制代码代码示例:

	[root@station230 lv0bak]# pvcreate /dev/sda14

	  Physical volume "/dev/sda14" successfully created

	[root@station230 lv0bak]# vgextend vg0 /dev/sda14

	  Volume group "vg0" successfully extended

移动数据：

复制代码代码示例:

	[root@station230 ~]# pvmove /dev/sda11 /dev/sda14

	  /dev/sda11: Moved: 100.0%

移出旧pv：

复制代码代码示例:

	[root@station230 ~]# vgreduce vg0 /dev/sda11

	  Removed "/dev/sda11" from volume group "vg0"

	[root@station230 ~]# cd /mnt/lv0

	[root@station230 lv0]# ls

	a  b  c  d  lost+found

迁移：

原来的主机：

复制代码代码示例:

	[root@station230 ~]# umount /dev/vg0/lv0 

	[root@station230 ~]# vgchange -a n vg0

	  0 logical volume(s) in volume group "vg0" now active

	[root@station230 ~]# vgexport vg0

	  Volume group "vg0" successfully exported

替换的主机：

复制代码代码示例:

	[root@station230 ~]# vgimport vg0

	  Volume group "vg0" successfully imported

	[root@station230 ~]# vgchange -a y vg0

	  1 logical volume(s) in volume group "vg0" now active

	[root@station230 ~]# mount /dev/vg0/lv0 /mnt/lv0

(责任编辑：IT)