许多Linux使用者安装操作系统时都会遇到这样的困境：如何精确评估和分配各个硬盘分区的容量，如果当初评估不准确，一旦系统分区不够用时可能不得不备份、删除相关数据，甚至被迫重新规划分区并重装操作系统，以满足应用系统的需要。
LVM是Linux环境中对磁盘分区进行管理的一种机制，是建立在硬盘和分区之上、文件系统之下的一个逻辑层，可提高磁盘分区管理的灵活性。RHEL5默认安装的分区格式就是LVM逻辑卷的格式，需要注意的是/boot分区不能基于LVM创建，必须独立出来。
一.LVM原理
要想理解好LVM的原理，我们必须首先要掌握4个基本的逻辑卷概念。
①PE (Physical Extend) 物理拓展
②PV (Physical Volume) 物理卷
③VG (Volume Group) 卷组
④LV (Logical Volume) 逻辑卷
我们知道在使用LVM对磁盘进行动态管理以后，我们是以逻辑卷的方式呈现给上层的服务的。所以我们所有的操作目的，其实就是去创建一个LV (Logical Volume),逻辑卷就是用来取代我们之前的分区，我们通过对逻辑卷进行格式化，然后进行挂载操作就可以使用了。那么LVM的工作原理是什么呢？所谓无图无真相，咱们下面通过图来对逻辑卷的原理进行解释！！
1.将我们的物理硬盘格式化成PV(Physical Volume)
我们看到，这里有两块硬盘，一块是sda，另一块是sdb，在LVM磁盘管理里，我首先要将这两块硬盘格式化为我们的PV (Physical Volume),也就是我们的物理卷，其实格式化物理卷的过程中LVM是将底层的硬盘划分为了一个一个的PE (Physical Extend),我们的LVM磁盘管理中PE的默认大小是4M大小 ，其实PE就是我们逻辑卷管理的最基本单位。比如说我有一个400M的硬盘，那么在将其格式化成PV的时候，其实际就是将这块物理硬盘划分成了100个的PE，因为PE默认的大小就是4M。这个就是我们的第一步操作。
2.创建一个VG(Volume Group)
在将硬盘格式化成PV以后，我们第二步操作就是创建一个卷组，也就是VG (Volume Group),卷组在这里我们可以将其抽象化成一个空间池，VG的作用就是用来装PE的，我们可以把一个或者多个PV加到VG当中，因为在第一步操作时就已经将该硬盘划分成了多个PE，所以将多个PV加到VG里面后，VG里面就存放了许许多多来自不同PV中的PE，我们通过上面的图片就可以看到，我们格式化了两块硬盘，每个硬盘分别格式化成了3个PE，然后将两块硬盘的PE都加到了我们的VG当中，那么我们的VG当中就包含了6个PE，这6个PE就是两个硬盘的PE之和。通常创建一个卷组的时候我们会为其取一个名字，也就是该VG的名字。
3.基于VG创建我们最后要使用的LV(Logical Volume)
【注意 】PV以及VG创建好以后我们是不能够直接使用的，因为PV、VG是我们逻辑卷底层的东西，我们其实最后使用的是在VG基础上创建的LV (Logical Volume),所以第三步操作就是基于VG来创建我们最终要使用的LV。
当我们创建好我们的VG以后，这个时候我们创建LV其实就是从VG中拿出我们指定数量的PE，还是拿上图来说，我们看到我们此时的VG里面已经拥有了6个PE，这时候我们创建了我们的第一个逻辑卷，它的大小是4个PE的大小，也就是16M(因为一个PE的默认大小是4M)，而这4个PE有三个是来自于第一块硬盘，而另外一个PE则是来自第二块硬盘。当我们创建第二个逻辑卷时，它的大小就最多只有两个PE的大小了，因为其中的4个PE已经分配给了我们的第一个逻辑卷。
所以创建逻辑卷其实就是我们从VG中拿出我们指定数量的PE，VG中的PE可以来自不同的PV，我们可以创建的逻辑卷的大小取决于VG当中PE存在的数量，并且我们创建的逻辑卷其大小一定是PE的整数倍(即逻辑卷的大小一定要是4M的整数倍)。
4.将我们创建好的LV进行文件系统的格式化，然后挂载使用
在创建好LV以后，这个时候我们就能够对其进行文件系统的格式化了，我们最终使用的就是我们刚创建好的LV，其就相当于传统的文件管理的分区，我们首先要对其进行文件系统的格式化操作，然后通过mount命令对其进行挂载，这个时候我们就能够像使用平常的分区一样来使用我们的逻辑卷了。
我们在创建好LV以后，我们会在 /dev 目录下看到我们的LV信息，例如 /dev/vgname/lvname， 我们每创建一个VG，其会在/dev目录下创建一个以该VG名字命名的文件夹，在该VG的基础上创建好LV以后，我们会在这个VG目录下多出一个以LV名字命名的逻辑卷。
下面我们来对整个LVM的工作原理进行一个总结：
(1)物理磁盘被格式化为PV，空间被划分为一个个的PE
(2)不同的PV加入到同一个VG中，不同PV的PE全部进入到了VG的PE池内
(3)LV基于PE创建，大小为PE的整数倍，组成LV的PE可能来自不同的物理磁盘
(4)LV直接可以格式化后挂载使用
(5)LV的扩充缩减实际上就是增加或减少组成该LV的PE数量，其过程不会丢失原始数据
我们看到，我们这里如果要对LV进行扩充，直接加进来一块sdc硬盘，然后将其格式化成PE，然后将该PV加入到了VG当中，这个时候我们就可以通过增加LV中PE的数量来动态的对LV进行扩充了，只要我们的LV的大小不要超过我们VG空余空间的大小就行!
二、创建LVM逻辑卷
熟悉了LVM的工作原理，首先是要将我们的物理硬盘格式化成PV，然后将多个PV加入到创建好的VG中，最后通过VG创建我们的LV。
三、拉伸一个逻辑卷
我们知道相比于传统磁盘管理方式的各种问题，使用LVM逻辑卷来管理我们的磁盘，我们可以对其进行动态的管理。在传统的磁盘管理方式中，我们如果出现分区大小不足的情况下，我们此时只能通过加入一块物理硬盘，然后对其进行分区，因为加入的硬盘作为独立的文件系统存在，所以对原有分区并没有影响，如果此时我们需要扩大分区，就只能先将之前的分区先卸载掉，然后将所有的信息转移到新的分区下，最后再将新的分区挂载上去，如果是在生产环境下，这样是不可想象的，正因为如此，我们才出现了LVM的磁盘管理方式，可以动态的对我们的磁盘进行管理。
我们首先来看下动态拉伸一个逻辑卷的示意图：
我们从上图可以看到，我们在对逻辑卷进行拉伸时，其实际就是向逻辑卷中增加PE的数量，而PE的数量是由VG中剩余PE的数量所决定的。
【注意： 】逻辑卷的拉伸操作可以在线进行，不需要卸载掉我们的逻辑卷
这样的好处就是当我们的逻辑卷的大小不够用时，我们不需要对其进行卸载，就可以动态的增加我们的逻辑卷的大小，并不会对我们的系统产生任何影响。例如如果我们的服务器上运行着一个重要的服务或者数据库，并要求我们7*24小时不间断保持在线，那么这样的动态增加逻辑卷的大小就非常的有必要了。
创建逻辑卷
创建磁盘分区
准备磁盘/dev/sdb进行分区
[root@manage ~]# fdisk /dev/sdb
The device presents a logical sector size that is smaller than
the physical sector size. Aligning to a physical sector (or optimal
I/O) size boundary is recommended, or performance may be impacted.
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.
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): 1
First sector (2048-209715199, default 2048):
Using default value 2048
Last sector, +sectors or +size{K,M,G} (2048-209715199, default 209715199): +20480M
Partition 1 of type Linux and of size 20 GiB is set
Command (m for help): n
Partition type:
p primary (1 primary, 0 extended, 3 free)
e extended
Select (default p): p
Partition number (2-4, default 2):
First sector (41945088-209715199, default 41945088):
Using default value 41945088
Last sector, +sectors or +size{K,M,G} (41945088-209715199, default 209715199): +20480M
Partition 2 of type Linux and of size 20 GiB is set
Command (m for help): n
Partition type:
p primary (2 primary, 0 extended, 2 free)
e extended
Select (default p): p
Partition number (3,4, default 3):
First sector (83888128-209715199, default 83888128):
Using default value 83888128
Last sector, +sectors or +size{K,M,G} (83888128-209715199, default 209715199): +20480M
Partition 3 of type Linux and of size 20 GiB is set
Command (m for help): n
Partition type:
p primary (3 primary, 0 extended, 1 free)
e extended
Select (default e): p
Selected partition 4
First sector (125831168-209715199, default 125831168):
Using default value 125831168
Last sector, +sectors or +size{K,M,G} (125831168-209715199, default 209715199):
Using default value 209715199
Partition 4 of type Linux and of size 40 GiB is set
Command (m for help): p
Disk /dev/sdb: 107.4 GB, 107374182400 bytes, 209715200 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk label type: dos
Disk identifier: 0x63d509ac
Device Boot Start End Blocks Id System
/dev/sdb1 2048 41945087 20971520 83 Linux
/dev/sdb2 41945088 83888127 20971520 83 Linux
/dev/sdb3 83888128 125831167 20971520 83 Linux
/dev/sdb4 125831168 209715199 41942016 83 Linux
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.刷新磁盘信息
[root@manage ~]# partprobe /dev/sdb创建物理卷
[root@manage ~]# pvcreate /dev/sdb[1-2]
WARNING: ext4 signature detected on /dev/sdb1 at offset 1080. Wipe it? [y/n]: y
Wiping ext4 signature on /dev/sdb1.
Physical volume "/dev/sdb1" successfully created.
Physical volume "/dev/sdb2" successfully created.
[root@manage ~]# pvdisplay
--- Physical volume ---
PV Name /dev/sda3
VG Name centos
PV Size 98.80 GiB / not usable 2.00 MiB
Allocatable yes
PE Size 4.00 MiB
Total PE 25293
Free PE 1
Allocated PE 25292
PV UUID rxE9e7-z7d1-RCZW-OUCR-37lX-2stt-ss3nTG
"/dev/sdb1" is a new physical volume of "20.00 GiB"
--- NEW Physical volume ---
PV Name /dev/sdb1
VG Name
PV Size 20.00 GiB
Allocatable NO
PE Size 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID dghIHv-uPHZ-4Pn2-HMVy-WOQl-EyPz-fjgrbi
"/dev/sdb2" is a new physical volume of "20.00 GiB"
--- NEW Physical volume ---
PV Name /dev/sdb2
VG Name
PV Size 20.00 GiB
Allocatable NO
PE Size 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID yWV7Nz-Mipv-ccDd-73Kn-IO1E-DCO1-J1kgB6创建Data_Db1卷组
[root@manage ~]# vgcreate Data_Db1 /dev/sdb[1-2]
Volume group "Data_Db1" successfully created
[root@manage ~]# vgdisplay
--- Volume group ---
VG Name centos
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 4
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 3
Open LV 3
Max PV 0
Cur PV 1
Act PV 1
VG Size 98.80 GiB
PE Size 4.00 MiB
Total PE 25293
Alloc PE / Size 25292 / <98.80 GiB
Free PE / Size 1 / 4.00 MiB
VG UUID TjkjQH-5P7M-fhba-kczk-RMsu-M3Rn-NWmrEz
--- Volume group ---
VG Name Data_Db1
System ID
Format lvm2
Metadata Areas 2
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 2
Act PV 2
VG Size 39.99 GiB
PE Size 4.00 MiB
Total PE 10238
Alloc PE / Size 0 / 0
Free PE / Size 10238 / 39.99 GiB
VG UUID ZJMjvj-2Cqe-IuqM-MJv0-8GDZ-rY4I-STzGsN创建总PE大小的逻辑卷
[root@manage ~]# lvcreate -n Data_DBs1 -l 10238 Data_Db1
Logical volume "Data_DBs1" created.
[root@manage ~]# lvdisplay
--- Logical volume ---
LV Path /dev/centos/swap
LV Name swap
VG Name centos
LV UUID TEche2-ARme-vfhG-sfNR-2r71-GNCh-47be6r
LV Write Access read/write
LV Creation host, time manage.ym68.cc, 2020-03-04 12:18:10 +0800
LV Status available
# open 2
LV Size 2.00 GiB
Current LE 512
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:1
--- Logical volume ---
LV Path /dev/centos/home
LV Name home
VG Name centos
LV UUID tti5Hf-xWXK-QSw9-7gNB-LEXQ-W5Yo-SQPTOl
LV Write Access read/write
LV Creation host, time manage.ym68.cc, 2020-03-04 12:18:10 +0800
LV Status available
# open 1
LV Size <46.80 GiB
Current LE 11980
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:2
--- Logical volume ---
LV Path /dev/centos/root
LV Name root
VG Name centos
LV UUID MhLNDC-EQAu-cLtR-gpNR-sIDx-sqWy-Bj9Vow
LV Write Access read/write
LV Creation host, time manage.ym68.cc, 2020-03-04 12:18:10 +0800
LV Status available
# open 1
LV Size 50.00 GiB
Current LE 12800
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:0
--- Logical volume ---
LV Path /dev/Data_Db1/Data_DBs1
LV Name Data_DBs1
VG Name Data_Db1
LV UUID a2oBiw-1O85-r2qe-bnZM-ABaw-DMQK-nLl0NF
LV Write Access read/write
LV Creation host, time manage.ym68.cc, 2020-03-23 12:15:24 +0800
LV Status available
# open 0
LV Size 39.99 GiB
Current LE 10238
Segments 2
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:3格式化逻辑卷并挂载
[root@manage ~]# mkfs.ext4 /dev/Data_Db1/Data_DBs1
mke2fs 1.42.9 (28-Dec-2013)
Discarding device blocks: done
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
2621440 inodes, 10483712 blocks
524185 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=2157969408
320 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
4096000, 7962624
Allocating group tables: done
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done
[root@manage ~]# mkdir /data
[root@manage ~]# mount /dev/Data_Db1/Data_DBs1 /data/
[root@manage ~]# df -Th |grep '/data$'
/dev/mapper/Data_Db1-Data_DBs1 ext4 40G 49M 38G 1% /data扩容逻辑卷
添加物理卷及添加至卷组
[root@manage ~]# pvcreate /dev/sdb3
Physical volume "/dev/sdb3" successfully created.
[root@manage ~]# vgextend Data_Db1 /dev/sdb3
Volume group "Data_Db1" successfully extended
[root@manage ~]# vgdisplay
--- Volume group ---
VG Name centos
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 4
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 3
Open LV 3
Max PV 0
Cur PV 1
Act PV 1
VG Size 98.80 GiB
PE Size 4.00 MiB
Total PE 25293
Alloc PE / Size 25292 / <98.80 GiB
Free PE / Size 1 / 4.00 MiB
VG UUID TjkjQH-5P7M-fhba-kczk-RMsu-M3Rn-NWmrEz
--- Volume group ---
VG Name Data_Db1
System ID
Format lvm2
Metadata Areas 3
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 3
VG Size <59.99 GiB
PE Size 4.00 MiB
Total PE 15357
Alloc PE / Size 10238 / 39.99 GiB
Free PE / Size 5119 / <20.00 GiB
VG UUID ZJMjvj-2Cqe-IuqM-MJv0-8GDZ-rY4I-STzGsN
[root@manage ~]# lvdisplay
--- Logical volume ---
LV Path /dev/centos/swap
LV Name swap
VG Name centos
LV UUID TEche2-ARme-vfhG-sfNR-2r71-GNCh-47be6r
LV Write Access read/write
LV Creation host, time manage.ym68.cc, 2020-03-04 12:18:10 +0800
LV Status available
# open 2
LV Size 2.00 GiB
Current LE 512
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:1
--- Logical volume ---
LV Path /dev/centos/home
LV Name home
VG Name centos
LV UUID tti5Hf-xWXK-QSw9-7gNB-LEXQ-W5Yo-SQPTOl
LV Write Access read/write
LV Creation host, time manage.ym68.cc, 2020-03-04 12:18:10 +0800
LV Status available
# open 1
LV Size <46.80 GiB
Current LE 11980
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:2
--- Logical volume ---
LV Path /dev/centos/root
LV Name root
VG Name centos
LV UUID MhLNDC-EQAu-cLtR-gpNR-sIDx-sqWy-Bj9Vow
LV Write Access read/write
LV Creation host, time manage.ym68.cc, 2020-03-04 12:18:10 +0800
LV Status available
# open 1
LV Size 50.00 GiB
Current LE 12800
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:0
--- Logical volume ---
LV Path /dev/Data_Db1/Data_DBs1
LV Name Data_DBs1
VG Name Data_Db1
LV UUID a2oBiw-1O85-r2qe-bnZM-ABaw-DMQK-nLl0NF
LV Write Access read/write
LV Creation host, time manage.ym68.cc, 2020-03-23 12:15:24 +0800
LV Status available
# open 1
LV Size 39.99 GiB
Current LE 10238
Segments 2
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:3扩容1G至逻辑卷
[root@manage ~]# lvextend -L +1G /dev/Data_Db1/Data_DBs1
Size of logical volume Data_Db1/Data_DBs1 changed from 39.99 GiB (10238 extents) to 40.99 GiB (10494 extents).
Logical volume Data_Db1/Data_DBs1 successfully resized.
[root@manage ~]# lvdisplay
--- Logical volume ---
LV Path /dev/centos/swap
LV Name swap
VG Name centos
LV UUID TEche2-ARme-vfhG-sfNR-2r71-GNCh-47be6r
LV Write Access read/write
LV Creation host, time manage.ym68.cc, 2020-03-04 12:18:10 +0800
LV Status available
# open 2
LV Size 2.00 GiB
Current LE 512
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:1
--- Logical volume ---
LV Path /dev/centos/home
LV Name home
VG Name centos
LV UUID tti5Hf-xWXK-QSw9-7gNB-LEXQ-W5Yo-SQPTOl
LV Write Access read/write
LV Creation host, time manage.ym68.cc, 2020-03-04 12:18:10 +0800
LV Status available
# open 1
LV Size <46.80 GiB
Current LE 11980
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:2
--- Logical volume ---
LV Path /dev/centos/root
LV Name root
VG Name centos
LV UUID MhLNDC-EQAu-cLtR-gpNR-sIDx-sqWy-Bj9Vow
LV Write Access read/write
LV Creation host, time manage.ym68.cc, 2020-03-04 12:18:10 +0800
LV Status available
# open 1
LV Size 50.00 GiB
Current LE 12800
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:0
--- Logical volume ---
LV Path /dev/Data_Db1/Data_DBs1
LV Name Data_DBs1
VG Name Data_Db1
LV UUID a2oBiw-1O85-r2qe-bnZM-ABaw-DMQK-nLl0NF
LV Write Access read/write
LV Creation host, time manage.ym68.cc, 2020-03-23 12:15:24 +0800
LV Status available
# open 1
LV Size 40.99 GiB
Current LE 10494
Segments 3
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:3取消挂载并检查分区完整性
如果是系统分区，则可以跳过。
[root@manage ~]# umount /data/
[root@manage ~]# e2fsck -f /dev/Data_Db1/Data_DBs1
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
/dev/Data_Db1/Data_DBs1: 20037/2621440 files (0.0% non-contiguous), 259016/10483712 blocks刷新磁盘容量信息
Ext4文件系统
[root@manage ~]# resize2fs /dev/Data_Db1/Data_DBs1
resize2fs 1.42.9 (28-Dec-2013)
Resizing the filesystem on /dev/Data_Db1/Data_DBs1 to 10745856 (4k) blocks.
The filesystem on /dev/Data_Db1/Data_DBs1 is now 10745856 blocks long.XFS文件系统只可扩容，不可减配
[root@manage ~]# xfs_growfs /dev/Data_Db1/Data_DBs1挂载逻辑卷查看容量
[root@manage ~]# mount /dev/Data_Db1/Data_DBs1 /data/
[root@manage ~]# df -Th |grep '/data$'
/dev/mapper/Data_Db1-Data_DBs1 ext4 41G 241M 38G 1% /data缩小逻辑卷
[root@manage ~]# umount /data/
[root@manage ~]# e2fsck -f /dev/Data_Db1/Data_DBs1
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
/dev/Data_Db1/Data_DBs1: 20037/2686976 files (0.0% non-contiguous), 263128/10745856 blocks
[root@manage ~]# resize2fs /dev/Data_Db1/Data_DBs1 40G
resize2fs 1.42.9 (28-Dec-2013)
Resizing the filesystem on /dev/Data_Db1/Data_DBs1 to 10485760 (4k) blocks.
The filesystem on /dev/Data_Db1/Data_DBs1 is now 10485760 blocks long.
[root@manage ~]# lvreduce -L 40G /dev/Data_Db1/Data_DBs1
WARNING: Reducing active logical volume to 40.00 GiB.
THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce Data_Db1/Data_DBs1? [y/n]: y
Size of logical volume Data_Db1/Data_DBs1 changed from 41.99 GiB (10750 extents) to 40.00 GiB (10240 extents).
Logical volume Data_Db1/Data_DBs1 successfully resized.
[root@manage ~]# mount /dev/Data_Db1/Data_DBs1 /data/
[root@manage ~]# df -Th |grep '/data$'
/dev/mapper/Data_Db1-Data_DBs1 ext4 40G 241M 37G 1% /data删除逻辑卷
[root@manage ~]# lvremove /dev/Data_Db1/Data_DBs1
Do you really want to remove active logical volume Data_Db1/Data_DBs1? [y/n]: y
Logical volume "Data_DBs1" successfully removed
[root@manage ~]# vgremove Data_Db1
Volume group "Data_Db1" successfully removed
[root@manage ~]# pvremove /dev/sdb[1-4]
PV /dev/sdb4 is used by VG Data_Db2 so please use vgreduce first.
(If you are certain you need pvremove, then confirm by using --force twice.)
/dev/sdb4: physical volume label not removed.
Labels on physical volume "/dev/sdb1" successfully wiped.
Labels on physical volume "/dev/sdb2" successfully wiped.
Labels on physical volume "/dev/sdb3" successfully wiped.
[root@manage ~]# lvs
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
home centos -wi-ao---- <46.80g
root centos -wi-ao---- 50.00g
swap centos -wi-ao---- 2.00g
[root@manage ~]# vgs
VG #PV #LV #SN Attr VSize VFree
Data_Db2 1 0 0 wz--n- <40.00g <40.00g
centos 1 3 0 wz--n- 98.80g 4.00m
[root@manage ~]# pvs
PV VG Fmt Attr PSize PFree
/dev/sda3 centos lvm2 a-- 98.80g 4.00m
/dev/sdb4 Data_Db2 lvm2 a-- <40.00g <40.00g逻辑卷快照
创建物理卷及卷组
[root@manage ~]# pvcreate /dev/sdb4
[root@manage ~]# vgcreate Data_Db2 /dev/sdb4-L 1G 表示此次创建快照大小
-s 表示创建快照
-n Data_Dbs2 表示新的快照名为Data_Dbs2
/dev/Data_Db1/Data_DBs1 为要创建快照的逻辑卷
[root@manage ~]# lvcreate -L 1G -s -n Data_Dbs2 /dev/Data_Db1/Data_DBs1
Logical volume "Data_Dbs2" created.
[root@manage ~]# lvdisplay
--- Logical volume ---
LV Path /dev/centos/swap
LV Name swap
VG Name centos
LV UUID TEche2-ARme-vfhG-sfNR-2r71-GNCh-47be6r
LV Write Access read/write
LV Creation host, time manage.ym68.cc, 2020-03-04 12:18:10 +0800
LV Status available
# open 2
LV Size 2.00 GiB
Current LE 512
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:1
--- Logical volume ---
LV Path /dev/centos/home
LV Name home
VG Name centos
LV UUID tti5Hf-xWXK-QSw9-7gNB-LEXQ-W5Yo-SQPTOl
LV Write Access read/write
LV Creation host, time manage.ym68.cc, 2020-03-04 12:18:10 +0800
LV Status available
# open 1
LV Size <46.80 GiB
Current LE 11980
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:2
--- Logical volume ---
LV Path /dev/centos/root
LV Name root
VG Name centos
LV UUID MhLNDC-EQAu-cLtR-gpNR-sIDx-sqWy-Bj9Vow
LV Write Access read/write
LV Creation host, time manage.ym68.cc, 2020-03-04 12:18:10 +0800
LV Status available
# open 1
LV Size 50.00 GiB
Current LE 12800
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:0
--- Logical volume ---
LV Path /dev/Data_Db1/Data_DBs1
LV Name Data_DBs1
VG Name Data_Db1
LV UUID a2oBiw-1O85-r2qe-bnZM-ABaw-DMQK-nLl0NF
LV Write Access read/write
LV Creation host, time manage.ym68.cc, 2020-03-23 12:15:24 +0800
LV snapshot status source of
Data_Dbs2 [active]
LV Status available
# open 1
LV Size 1.00 GiB
Current LE 256
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:3
--- Logical volume ---
LV Path /dev/Data_Db1/Data_Dbs2
LV Name Data_Dbs2
VG Name Data_Db1
LV UUID Fsoklv-9MYF-2jQv-eDKe-U1GK-M4Zr-Q4QYr9
LV Write Access read/write
LV Creation host, time manage.ym68.cc, 2020-03-23 12:55:36 +0800
LV snapshot status active destination for Data_DBs1
LV Status available
# open 0
LV Size 1.00 GiB
Current LE 256
COW-table size 1.00 GiB
COW-table LE 256
Allocated to snapshot 0.01%
Snapshot chunk size 4.00 KiB
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:6还原逻辑卷快照
删除文件
[root@manage ~]# echo "test123" > /data/cs.log
[root@manage ~]# cd /data/
[root@manage data]# ls
cs.log docker lost+found nginx-1.17.8 nginx-1.17.8.tar.gz php-7.4.3 php-7.4.3.tar.gz vsftpd-3.0.3 vsftpd-3.0.3.tar.gz
[root@manage data]# rm -rf *还原文件
[root@manage ~]# umount /data/
[root@manage ~]# lvconvert --merge /dev/Data_Db1/Data_Dbs2
Merging of volume Data_Db1/Data_Dbs2 started.
Data_Db1/Data_DBs1: Merged: 99.41%
Data_Db1/Data_DBs1: Merged: 100.00%
[root@manage ~]# mount /dev/Data_Db1/Data_DBs1 /data/
[root@manage ~]# ls /data/
cs.log docker lost+found nginx-1.17.8 nginx-1.17.8.tar.gz php-7.4.3 php-7.4.3.tar.gz vsftpd-3.0.3 vsftpd-3.0.3.tar.gz
[root@manage ~]# cat /data/cs.log
test123
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