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linux lvm 镜像,LVM实现逻辑卷镜像

作者：2023面试高手 | 2024-06-05 03:16:56

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lvm镜像

本文系统 Centos 6.5 x64

LVM的镜像功能，有点儿类似于Raid1，即多块儿磁盘互相同步，确保资料不会丢失。

1、在此添加4块物理硬盘，每块2G空间

2、将sdb、sdc、sdd、sde 创建物理卷，将sdb、sdc、sdd 添加卷组到vmTest[root@node4 ~]# pvcreate /dev/sdb

Physical volume "/dev/sdb" successfully created

[root@node4 ~]# pvcreate /dev/sdc

Physical volume "/dev/sdc" successfully created

[root@node4 ~]# pvcreate /dev/sdd

Physical volume "/dev/sdd" successfully created

[root@node4 ~]# pvcreate /dev/sde

Physical volume "/dev/sde" successfully created[root@node4 ~]# vgcreate vgTest /dev/sdb /dev/sdc /dev/sdd

Volume group "vgTest" successfully created

[root@node4 ~]#

3、创建逻辑卷[root@node4 ~]# lvcreate -L 1G -m1 -n lvTest vgTest /dev/sdb /dev/sdc /dev/sdd

Logical volume "lvTest" created

查看lvs信息[root@node4 ~]# lvs -a -o +devices

LV VG Attr LSize Pool Origin Data% Move Log Cpy%Sync Convert Devices

lv_root VolGroup -wi-ao---- 8.54g /dev/sda2(0)

lv_swap VolGroup -wi-ao---- 992.00m /dev/sda2(2186)

lvTest vgTest mwi-a-m--- 1.00g lvTest_mlog 100.00 lvTest_mp_w_picpath_0(0),lvTest_mp_w_picpath_1(0)

[lvTest_mp_w_picpath_0] vgTest iwi-aom--- 1.00g /dev/sdb(0)

[lvTest_mp_w_picpath_1] vgTest iwi-aom--- 1.00g /dev/sdc(0)

[lvTest_mlog] vgTest lwi-aom--- 4.00m /dev/sdd(0)

LVM镜像需要用到-m1参数，从上面可以看出，/dev/sdb和/dev/sdc互为镜像，而/dev/sdd作为日志存储使用

4、格式化分区，在逻辑卷上创建一个文件。对/dev/sdc进行破坏。[root@node4 ~]# mkfs.ext4 /dev/vgTest/lvTest

mke2fs 1.41.12 (17-May-2010)

文件系统标签=

操作系统:Linux

块大小=4096 (log=2)

分块大小=4096 (log=2)

Stride=0 blocks, Stripe width=0 blocks

65536 inodes, 262144 blocks

13107 blocks (5.00%) reserved for the super user

第一个数据块=0

Maximum filesystem blocks=268435456

8 block groups

32768 blocks per group, 32768 fragments per group

8192 inodes per group

Superblock backups stored on blocks:

32768, 98304, 163840, 229376

正在写入inode表: 完成

Creating journal (8192 blocks): 完成

Writing superblocks and filesystem accounting information: 完成

This filesystem will be automatically checked every 31 mounts or

180 days, whichever comes first. Use tune2fs -c or -i to override.[root@node4 ~]# dd if=/dev/zero of=/dev/sdc count=10 bs=20M

记录了10+0 的读入

记录了10+0 的写出

209715200字节(210 MB)已复制，2.08666 秒，101 MB/秒

[root@node4 ~]# lvs -a -o +devices

Couldn't find device with uuid zecO8D-2Suc-rnmK-a2Z7-6613-Zy1X-whVS0X.

LV VG Attr LSize Pool Origin Data% Move Log Cpy%Sync Convert Devices

lv_root VolGroup -wi-ao---- 8.54g /dev/sda2(0)

lv_swap VolGroup -wi-ao---- 992.00m /dev/sda2(2186)

lvTest vgTest mwi-a-m-p- 1.00g lvTest_mlog 100.00 lvTest_mp_w_picpath_0(0),lvTest_mp_w_picpath_1(0)

[lvTest_mp_w_picpath_0] vgTest iwi-aom--- 1.00g /dev/sdb(0)

[lvTest_mp_w_picpath_1] vgTest iwi-aom-p- 1.00g unknown device(0)

[lvTest_mlog] vgTest lwi-aom--- 4.00m /dev/sdd(0)

[root@node4 ~]# lvscan

Couldn't find device with uuid zecO8D-2Suc-rnmK-a2Z7-6613-Zy1X-whVS0X.

ACTIVE '/dev/vgTest/lvTest' [1.00 GiB] inherit

ACTIVE '/dev/VolGroup/lv_root' [8.54 GiB] inherit

ACTIVE '/dev/VolGroup/lv_swap' [992.00 MiB] inherit

[root@node4 ~]#

重新挂载逻辑卷，确认文件可以正常读取[root@node4 ~]# mkdir /lvmTest

[root@node4 ~]# mount /dev/vgTest/lvTest /lvmTest/

[root@node4 ~]# cd /lvmTest/

[root@node4 lvmTest]# ls

lost+found

[root@node4 lvmTest]# echo "ac" > ac

[root@node4 lvmTest]# cat ac

[root@node4 lvmTest]#

将卷组中坏掉的物理卷(/dev/sdc)移除：[root@node4 lvmTest]# vgdisplay

Couldn't find device with uuid zecO8D-2Suc-rnmK-a2Z7-6613-Zy1X-whVS0X.

--- Volume group ---

VG Name vgTest

System ID

Format lvm2

Metadata Areas 2

Metadata Sequence No 3

VG Access read/write

VG Status resizable

MAX LV 0

Cur LV 1

Open LV 1

Max PV 0

Cur PV 3

Act PV 2

VG Size 5.99 GiB

PE Size 4.00 MiB

Total PE 1533

Alloc PE / Size 513 / 2.00 GiB

Free PE / Size 1020 / 3.98 GiB

VG UUID 1qzO3A-Tjvi-by9l-Oq49-byz3-tIkx-rfSqex[root@node4 lvmTest]# vgreduce --removemissing --force vgTest

Couldn't find device with uuid zecO8D-2Suc-rnmK-a2Z7-6613-Zy1X-whVS0X.

Wrote out consistent volume group vgTest

[root@node4 lvmTest]#

5、向卷组中加入新的物理卷(/dev/sde)：[root@node4 lvmTest]# vgextend vgTest /dev/sde

Volume group "vgTest" successfully extended

[root@node4 lvmTest]#

6、进行数据恢复(过程中无须解除逻辑卷的挂载)[root@node4 lvmTest]# lvconvert -m1 /dev/vgTest/lvTest /dev/sdb /dev/sdd /dev/sde

vgTest/lvTest: Converted: 0.0%

vgTest/lvTest: Converted: 100.0%

[root@node4 lvmTest]# lvs -a -o +devices

LV VG Attr LSize Pool Origin Data% Move Log Cpy%Sync Convert Devices

lv_root VolGroup -wi-ao---- 8.54g /dev/sda2(0)

lv_swap VolGroup -wi-ao---- 992.00m /dev/sda2(2186)

lvTest vgTest mwi-aom--- 1.00g lvTest_mlog 100.00 lvTest_mp_w_picpath_0(0),lvTest_mp_w_picpath_1(0)

[lvTest_mp_w_picpath_0] vgTest iwi-aom--- 1.00g /dev/sdb(0)

[lvTest_mp_w_picpath_1] vgTest iwi-aom--- 1.00g /dev/sdd(0)

[lvTest_mlog] vgTest lwi-aom--- 4.00m /dev/sde(0)

7、核实原数据[root@node4 lvmTest]# cat ac

[root@node4 lvmTest]# echo "abcde" >> ac

[root@node4 lvmTest]# cat ac

abcde

[root@node4 lvmTest]#[root@node4 lvmTest]# lvdisplay

--- Logical volume ---

LV Path /dev/vgTest/lvTest

LV Name lvTest

VG Name vgTest

LV UUID a8kDmI-R3ls-SfKJ-qx3d-1Tbb-wPAd-TJcQfn

LV Write Access read/write

LV Creation host, time node4.lansgg.com, 2015-09-10 20:50:41 +0800

LV Status available

# open 1

LV Size 1.00 GiB

Current LE 256

Mirrored volumes 2

Segments 1

Allocation inherit

Read ahead sectors auto

- currently set to 256

Block device 253:5

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