逻辑卷镜像

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1.分区：

1.1.创建分区：

[root@localhost~]# fdisk /dev/sdc

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)

Partition number (1-4): 3

First cylinder (5-2610, default 5):

Using default value 5

Last cylinder, +cylinders or +size{K,M,G}(5-2610, default 2610): +30M

Command (m for help): w

The partition table has been altered!

Calling ioctl() to re-read partition table.

Syncing disks.

1.2.查看分区情况：

[root@localhost~]# fdisk -l

Disk /dev/sda: 21.5 GB, 21474836480 bytes

255 heads, 63 sectors/track, 2610 cylinders

Units = cylinders of 16065 * 512 = 8225280bytes

Sector size (logical/physical): 512 bytes /512 bytes

I/O size (minimum/optimal): 512 bytes / 512bytes

Disk identifier: 0x000abc53

Device Boot Start End Blocks Id System

/dev/sda1 * 1 64 512000 83 Linux

Partition 1 does not end on cylinderboundary.

/dev/sda2 64 2611 20458496 8e Linux LVM

Disk /dev/sdb: 21.5 GB, 21474836480 bytes

255 heads, 63 sectors/track, 2610 cylinders

Units = cylinders of 16065 * 512 = 8225280bytes

Sector size (logical/physical): 512 bytes /512 bytes

I/O size (minimum/optimal): 512 bytes / 512bytes

Disk identifier: 0x5449b42b

Device Boot Start End Blocks Id System

/dev/sdb1 1 7 56196 83 Linux

/dev/sdb2 8 11 32130 83 Linux

Disk /dev/sdc: 21.5 GB, 21474836480 bytes

255 heads, 63 sectors/track, 2610 cylinders

Units = cylinders of 16065 * 512 = 8225280bytes

Sector size (logical/physical): 512 bytes /512 bytes

I/O size (minimum/optimal): 512 bytes / 512bytes

Disk identifier: 0xe8f6c09c

Device Boot Start End Blocks Id System

/dev/sdc1 1 4 32098+ 83 Linux

/dev/sdc3 5 9 40162+ 83 Linux

Disk /dev/mapper/VolGroup-lv_root: 18.7 GB,18698207232 bytes

255 heads, 63 sectors/track, 2273 cylinders

Units = cylinders of 16065 * 512 = 8225280bytes

Sector size (logical/physical): 512 bytes /512 bytes

I/O size (minimum/optimal): 512 bytes / 512bytes

Disk identifier: 0x00000000

Disk /dev/mapper/VolGroup-lv_swap: 2248 MB,2248146944 bytes

255 heads, 63 sectors/track, 273 cylinders

Units = cylinders of 16065 * 512 = 8225280bytes

Sector size (logical/physical): 512 bytes /512 bytes

I/O size (minimum/optimal): 512 bytes / 512bytes

Disk identifier: 0x00000000

2.创建卷

2.1.创建物理卷：

[root@localhost ~]# pvcreate /dev/sdb1

Physical volume "/dev/sdb1" successfully created

[root@localhost ~]# pvcreate /dev/sdb2

Physical volume "/dev/sdb2" successfully created

[root@localhost ~]# pvcreate /dev/sdc1

Physical volume "/dev/sdc1" successfully created

[root@localhost ~]# pvcreate /dev/sdc3

Physical volume "/dev/sdc3" successfully created

2.2.创建卷组：

[root@localhost~]# vgcreate vg0 /dev/sdb1 /dev/sdc1

Volume group "vg0" successfullycreated

2.3.创建逻辑卷镜像：

[root@localhost~]# lvcreate -L 20M -m1 -n mirror /dev/vg0

Logical volume "mirror" created

3.对逻辑卷的处理

3.1．格式化硬盘：

[root@localhost~]# mkfs.ext4 /dev/vg0/mirror

3.2．创建挂载点：

[root@localhost~]# mkdir /mirror

3.3. 挂载硬盘：

root@localhost~]# mount /dev/vg0/mirror /mirror

[root@localhost~]# cd /mirror

[root@localhostmirror]# ls

lost+found

4.查看日志：

Aug 1504:27:47 localhost kernel: device-mapper: dm-log-userspace: version 1.1.0loaded

Aug 1504:28:13 localhost lvm[1002]: Monitoring mirror device vg0-mirror for events.

Aug 1504:28:13 localhost lvm[1002]: vg0-mirror is now in-sync.

5.破坏逻辑卷镜像

5.1. 查看正常的逻辑卷情况：

[root@localhost mirror]# lvs -a -o devices

Devices

/dev/sda2(0)

/dev/sda2(4458)

mirror_mimage_0(0),mirror_mimage_1(0)

/dev/sdb1(0)

/dev/sdc1(0)

/dev/sdc1(5)

5.2. 破坏镜像lvm，删除/dev/sdc1

[root@localhostmirror]# dd if=/dev/zero of=/dev/sdc1 count=10

10+0records in

10+0records out

5120bytes (5.1 kB) copied, 0.00544565 s, 940 kB/s

5.3. 查看破坏后的逻辑卷情况：

[root@localhostmirror]# lvs -a -o devices

Couldn't find device with uuiddjiZ7N-IOMf-Ix9S-xFic-BgrD-FAm4-AZ8PBq.

Devices

/dev/sda2(0)

/dev/sda2(4458)

mirror_mimage_0(0),mirror_mimage_1(0)

/dev/sdb1(0)

unknown device(0)

unknown device(5)

5.4.逻辑卷仍然可以用：

[root@localhost mirror]# lvscan

Couldn't find device with uuid djiZ7N-IOMf-Ix9S-xFic-BgrD-FAm4-AZ8PBq.

ACTIVE '/dev/vg0/mirror' [20.00 MiB] inherit

ACTIVE '/dev/VolGroup/lv_root' [17.41 GiB] inherit

ACTIVE '/dev/VolGroup/lv_swap' [2.09 GiB] inherit

5.5.逻辑卷镜像的恢复：

5.5.1. 在vg0新加一个pv，对数据进行恢复：

[root@localhostmirror]# vgextend vg0 /dev/sdc3

Volume group "vg0" successfullyextended

5.5.2. 用/dev/sdc3替换坏掉的/dev/sdc1

[root@localhostmirror]# lvconvert -m1 /dev/vg0/mirror /dev/sdc3 /dev/sdb1

vg0/mirror: Converted: 20.0%

vg0/mirror: Converted: 100.0%

/dev/sdc1 已经被/dev/sdc3 取代了

[root@localhostmirror]# lvs -a -o devices

Devices

/dev/sda2(0)

/dev/sda2(4458)

mirror_mimage_0(0),mirror_mimage_1(0)

/dev/sdb1(0)

/dev/sdc3(0)

/dev/sdc3(5)

查看镜像状态：已经恢复

[root@localhostmirror]# lvdisplay /dev/vg0/mirror

--- Logical volume ---

LV Path /dev/vg0/mirror

LV Name mirror

VG Name vg0

LV UUID CRAaF2-cPVL-5pja-6ceW-QWCp-aRiJ-WgMhx2

LV Write Access read/write

LV Creation host, time localhost.localdomain,2014-08-15 04:28:12 +0800

LV Status available

# open 1

LV Size 20.00 MiB

Current LE 5

Mirrored volumes 2

Segments 1

Allocation inherit

Read ahead sectors auto

- currently set to 256

Block device 253:5

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