系统版本:
[root@centos71d1 ~]# cat /etc/redhat-release
CentOS Linux release 7.1.1503 (Core)
[root@centos71d1 ~]# uname -r
3.10.0-229.el7.x86_64
以下演示LVM的基本操作：
1. PV的创建、查看、移除
2. VG的创建、查看、扩展、缩减
3. LV的创建、查看、扩展、缩减、快照、移除
在VMware虚拟机中添加2块10GB的硬盘
[root@centos71d1 ~]# fdisk -l | grep -i "disk /dev/sd"
Disk /dev/sdc: 10.7 GB, 10737418240 bytes, 20971520 sectors
Disk /dev/sda: 21.5 GB, 21474836480 bytes, 41943040 sectors
Disk /dev/sdb: 10.7 GB, 10737418240 bytes, 20971520 sectors
#除了sda，sdb和sdc为新添加的硬盘
PV的创建、查看、移除
对/dev/sdb分区和格式化，并设置分区为“Linux LVM”格式
[root@centos71d1 ~]# fdisk /dev/sdb
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.
Device does not contain a recognized partition table
Building a new DOS disklabel with disk identifier 0xc98da444.
Command (m for help): n
#新建分区
Partition type:
p primary (0 primary, 0 extended, 4 free)
e extended
Select (default p): p
#选择创建主分区
Partition number (1-4, default 1):
#默认选择分区号为1
First sector (2048-20971519, default 2048):
#起始扇区，按默认
Using default value 2048
Last sector, +sectors or +size{K,M,G} (2048-20971519, default 20971519):
#结束扇区，这里只分一个区，因此按默认，指定最后一个扇区
Using default value 20971519
Partition 1 of type Linux and of size 10 GiB is set
Command (m for help): t
#更改分区类型
Selected partition 1
Hex code (type L to list all codes): 8e
#8e为Linux LVM的代码
Changed type of partition 'Linux' to 'Linux LVM'
Command (m for help): p
#显示分区表，可以看到已经创建好的/dev/sdb1分区
Disk /dev/sdb: 10.7 GB, 10737418240 bytes, 20971520 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: 0xc98da444
Device Boot Start End Blocks Id System
/dev/sdb1 2048 20971519 10484736 8e Linux LVM
Command (m for help): w
#保存退出
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
[root@centos71d1 ~]# partprobe
#刷新分区表
Warning: Unable to open /dev/sr0 read-write (Read-only file system). \
/dev/sr0 has been opened read-only.
Warning: Unable to open /dev/sr0 read-write (Read-only file system). \
/dev/sr0 has been opened read-only.
Warning: Unable to open /dev/sr0 read-write (Read-only file system). \
/dev/sr0 has been opened read-only.
PV的创建
[root@centos71d1 ~]# pvcreate /dev/sdb1
#创建PV /dev/sdb1
Physical volume "/dev/sdb1" successfully created
PV的查看
[root@centos71d1 ~]# pvs
#查看简要的PV信息
PV VG Fmt Attr PSize PFree
/dev/sda2 centos lvm2 a-- 19.51g 40.00m
/dev/sdb1 lvm2 --- 10.00g 10.00g
[root@centos71d1 ~]# pvdisplay /dev/sdb1
#查看PV /dev/sdb1的详细信息
"/dev/sdb1" is a new physical volume of "10.00 GiB"
--- NEW Physical volume ---
PV Name /dev/sdb1
VG Name
PV Size 10.00 GiB
Allocatable NO
PE Size 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID 4XdGpd-80lY-cDtZ-vPQn-mWPZ-c469-7r3At5
PV的移除
[root@centos71d1 ~]# pvremove /dev/sdb1
#移除PV /dev/sdb1
Labels on physical volume "/dev/sdb1" successfully wiped
VG的创建、查看、扩展、缩减
VG的创建
[root@centos71d1 ~]# pvcreate /dev/sdb1
#把前面移除的PV /dev/sdb1创建回来
Physical volume "/dev/sdb1" successfully created
[root@centos71d1 ~]# vgcreate -s 16M myvg /dev/sdb1
#使用PV /dev/sdb1创建VG myvg，指定PE大小为16MB
Volume group "myvg" successfully created
VG的查看
[root@centos71d1 ~]# vgs
#查看简要的VG信息
VG #PV #LV #SN Attr VSize VFree
centos 1 2 0 wz--n- 19.51g 40.00m
myvg 1 0 0 wz--n- 9.98g 9.98g
[root@centos71d1 ~]# vgdisplay myvg
#查看VG myvg的详细信息
--- Volume group ---
VG Name myvg
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 1
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 0
Open LV 0
Max PV 0
Cur PV 1
Act PV 1
VG Size 9.98 GiB
PE Size 16.00 MiB
Total PE 639
Alloc PE / Size 0 / 0
Free PE / Size 639 / 9.98 GiB
VG UUID WoszmO-0t4v-EYWr-Rk0Y-UgKt-f1rt-w8I1l9
VG的扩展
和前面一样，在硬盘/dev/sdc上，分一个区，格式化为Linux LVM格式
[root@centos71d1 ~]# fdisk /dev/sdc
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.
Device does not contain a recognized partition table
Building a new DOS disklabel with disk identifier 0x28ebc5c0.
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 (2048-20971519, default 2048):
Using default value 2048
Last sector, +sectors or +size{K,M,G} (2048-20971519, default 20971519):
Using default value 20971519
Partition 1 of type Linux and of size 10 GiB is set
Command (m for help): t
Selected partition 1
Hex code (type L to list all codes): 8e
Changed type of partition 'Linux' to 'Linux LVM'
Command (m for help): p
Disk /dev/sdc: 10.7 GB, 10737418240 bytes, 20971520 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: 0x28ebc5c0
Device Boot Start End Blocks Id System
/dev/sdc1 2048 20971519 10484736 8e Linux LVM
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
[root@centos71d1 ~]# partprobe
Warning: Unable to open /dev/sr0 read-write (Read-only file system). \
/dev/sr0 has been opened read-only.
Warning: Unable to open /dev/sr0 read-write (Read-only file system). \
/dev/sr0 has been opened read-only.
Warning: Unable to open /dev/sr0 read-write (Read-only file system). \
/dev/sr0 has been opened read-only.
[root@centos71d1 ~]# pvcreate /dev/sdc1
Physical volume "/dev/sdc1" successfully created
[root@centos71d1 ~]# vgextend myvg /dev/sdc1
#添加PV /dev/sdc1，扩展VG myvg
Volume group "myvg" successfully extended
[root@centos71d1 ~]# vgdisplay myvg
--- Volume group ---
VG Name myvg
System ID
Format lvm2
Metadata Areas 2
Metadata Sequence No 2
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 0
Open LV 0
Max PV 0
Cur PV 2
Act PV 2
VG Size 19.97 GiB
PE Size 16.00 MiB
Total PE 1278
Alloc PE / Size 0 / 0
Free PE / Size 1278 / 19.97 GiB
VG UUID WoszmO-0t4v-EYWr-Rk0Y-UgKt-f1rt-w8I1l9
#可以看到VG的空间增加到近20GB
VG的缩减
[root@centos71d1 ~]# pvmove /dev/sdb1
No data to move for myvg
#先移动PV /dev/sdb1中的数据到VG myvg中的其它PV；因为现在没有数据，所以出现上面的提示
[root@centos71d1 ~]# vgreduce myvg /dev/sdb1
Removed "/dev/sdb1" from volume group "myvg"
#将PV /dev/sdb1从VG myvg中移除
[root@centos71d1 ~]# vgdisplay myvg
--- Volume group ---
VG Name myvg
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 3
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 0
Open LV 0
Max PV 0
Cur PV 1
Act PV 1
VG Size 9.98 GiB
PE Size 16.00 MiB
Total PE 639
Alloc PE / Size 0 / 0
Free PE / Size 639 / 9.98 GiB
VG UUID WoszmO-0t4v-EYWr-Rk0Y-UgKt-f1rt-w8I1l9
#可以看到VG myvg的空间又变成了9.98GiB
[root@centos71d1 ~]# vgextend myvg /dev/sdb1
Volume group "myvg" successfully extended
#再次将/dev/sdb1加回myvg
LV的创建、查看、扩展、缩减、快照、移除
LV的创建
[root@centos71d1 ~]# lvcreate -L 12G -n mylv myvg
Logical volume "mylv" created.
#在VG myvg中创建LV mylv，大小为12GB
[root@centos71d1 ~]# mke2fs -t ext4 -L MYLV -b 1024 /dev/myvg/mylv
#格式化LV mylv的文件系统为ext4格式，指定label为MYLV，块大小为1024 bytes
mke2fs 1.42.9 (28-Dec-2013)
Filesystem label=MYLV
OS type: Linux
Block size=1024 (log=0)
Fragment size=1024 (log=0)
Stride=0 blocks, Stripe width=0 blocks
786432 inodes, 12582912 blocks
629145 blocks (5.00%) reserved for the super user
First data block=1
Maximum filesystem blocks=46137344
1536 block groups
8192 blocks per group, 8192 fragments per group
512 inodes per group
Superblock backups stored on blocks:
8193, 24577, 40961, 57345, 73729, 204801, 221185, 401409, 663553,
1024001, 1990657, 2809857, 5120001, 5971969
Allocating group tables: done
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done
[root@centos71d1 ~]# mkdir /backup
[root@centos71d1 ~]# mount /dev/myvg/mylv /backup/
#将LV mylv挂载至/backup目录
[root@centos71d1 ~]# mount | tail -1
#mount显示最后一行，可以看到已经成功挂载，/dev/myvg/mylv实际指向/dev/mapper/myvg-mylv
/dev/mapper/myvg-mylv on /backup type ext4 (rw,relatime,data=ordered)
[root@centos71d1 ~]# cp /etc/grub2.cfg /backup/
[root@centos71d1 ~]# ls /backup/
grub2.cfg lost+found
LV的查看
[root@centos71d1 ~]# lvdisplay /dev/myvg/mylv
#查看LV mylv的详细信息
--- Logical volume ---
LV Path /dev/myvg/mylv
LV Name mylv
VG Name myvg
LV UUID GgtQzX-3jfe-KVMX-tvOe-Sp35-GpWG-PJCE5w
LV Write Access read/write
LV Creation host, time centos71d1, 2018-07-05 13:49:13 +0800
LV Status available
# open 1
LV Size 12.00 GiB
Current LE 768
Segments 2
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:2
LV的扩展
[root@centos71d1 ~]# vgdisplay myvg
--- Volume group ---
VG Name myvg
System ID
Format lvm2
Metadata Areas 2
Metadata Sequence No 5
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 1
Open LV 1
Max PV 0
Cur PV 2
Act PV 2
VG Size 19.97 GiB
PE Size 16.00 MiB
Total PE 1278
Alloc PE / Size 768 / 12.00 GiB
Free PE / Size 510 / 7.97 GiB
VG UUID WoszmO-0t4v-EYWr-Rk0Y-UgKt-f1rt-w8I1l9
#VG myvg中还有近8GB的空间
[root@centos71d1 ~]# lvextend -L 16G /dev/myvg/mylv
#扩展LV mylv的空间到16GB
Size of logical volume myvg/mylv changed from 12.00 GiB (768 extents) to \
16.00 GiB (1024 extents).
Logical volume mylv successfully resized
[root@centos71d1 ~]# resize2fs /dev/myvg/mylv
#调整文件系统大小，没有指定大小，表示使用所有可用空间
resize2fs 1.42.9 (28-Dec-2013)
Filesystem at /dev/myvg/mylv is mounted on /backup; on-line resizing required
old_desc_blocks = 96, new_desc_blocks = 128
The filesystem on /dev/myvg/mylv is now 16777216 blocks long.
[root@centos71d1 ~]# df -lh
#使用df命令查看文件系统信息
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/centos-root 18G 948M 17G 6% /
devtmpfs 481M 0 481M 0% /dev
tmpfs 490M 0 490M 0% /dev/shm
tmpfs 490M 6.6M 484M 2% /run
tmpfs 490M 0 490M 0% /sys/fs/cgroup
/dev/sda1 497M 120M 378M 24% /boot
/dev/mapper/myvg-mylv 16G 3.3M 15G 1% /backup
LV的缩减
#LV的缩减，可能会损毁数据，因此在该操作之前，要确保已经做好数据备份；
#并且要先查看分区已使用的大小，确认要缩减多少空间，缩减到的大小不能小于原文件系统已使用的空间大小
[root@centos71d1 ~]# umount /backup/
#先卸载
[root@centos71d1 ~]# e2fsck -f /dev/myvg/mylv
#强制检查分区错误
e2fsck 1.42.9 (28-Dec-2013)
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
MYLV: 12/1048576 files (0.0% non-contiguous), 304322/16777216 blocks
[root@centos71d1 ~]# resize2fs /dev/myvg/mylv 12G
#先缩减文件系统到12GB
resize2fs 1.42.9 (28-Dec-2013)
Resizing the filesystem on /dev/myvg/mylv to 12582912 (1k) blocks.
The filesystem on /dev/myvg/mylv is now 12582912 blocks long.
[root@centos71d1 ~]# lvreduce -L 12G /dev/myvg/mylv
#再调整LV mylv到12GB
WARNING: Reducing active logical volume to 12.00 GiB
THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce mylv? [y/n]: y
Size of logical volume myvg/mylv changed from 16.00 GiB (1024 extents) to \
12.00 GiB (768 extents).
Logical volume mylv successfully resized
[root@centos71d1 ~]# mount /dev/myvg/mylv /backup/
#重新挂载
[root@centos71d1 ~]# ls /backup/
grub2.cfg lost+found
#运气不错，数据没有丢失
LV的快照
#对某个LV创建快照，快照的功能类似于硬链接，因此创建的快照会与原LV处于同一个VG中
[root@centos71d1 ~]# cp /etc/issue /backup/
[root@centos71d1 ~]# ls /backup/
grub2.cfg issue lost+found
[root@centos71d1 ~]# lvcreate -s -L 2G -p r -n mylv-snap /dev/myvg/mylv
Logical volume "mylv-snap" created.
#创建LV mylv的快照mylv-snap，大小为2GB，权限为只读
[root@centos71d1 ~]# mount /dev/myvg/mylv-snap /mnt/
mount: /dev/mapper/myvg-mylv--snap is write-protected, mounting read-only
#将快照卷挂载至/mnt目录
[root@centos71d1 ~]# vim /backup/issue
[root@centos71d1 ~]# cat /backup/issue
CentOS release 6.7 (Final)
Kernel \r on an \m
new line
#添加一行“new line”
[root@centos71d1 ~]# cat /mnt/issue
\S
Kernel \r on an \m
#快照卷中对应的文件没有“new line”
LV的移除
[root@centos71d1 ~]# cp -a /mnt/grub2.cfg /tmp
[root@centos71d1 ~]# cp -a /mnt/issue /tmp
#备份快照卷中的数据
[root@centos71d1 ~]# umount /mnt/
[root@centos71d1 ~]# lvremove /dev/myvg/mylv-snap
Do you really want to remove active logical volume mylv-snap? [y/n]: y
Logical volume "mylv-snap" successfully removed
#删除快照卷