Linux 逻辑卷管理
管理员可以在卷组上任意创建逻辑卷，并进一步在逻辑卷上创建文件系统。简单地说：卷组由多个物理卷组成，可以在卷组中创建多个逻辑卷，对逻辑卷创建文件系统给用户使用。如果卷组空间中有多余的物理卷或者物理卷容量小需要更换，则可以将物理卷从卷组中剔除。如果逻辑卷空间充足，希望将多余的空间缩减出来它用，也可以缩减逻辑卷空间。如果卷组空间不足，可以通过添加新的物理卷到卷组中，以扩展卷组容量。如果逻辑卷空间不足，在
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Linux 逻辑卷管理
文章目录
环境准备
虚拟机添加3块20G硬盘，sdb sdc sdd
[root@centos7 ~]# lsblk /dev/sd{b..d}
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sdb 8:16 0 20G 0 disk
sdc 8:32 0 20G 0 disk
sdd 8:48 0 20G 0 disk
逻辑卷基本管理
硬盘分区管理方案缺点
- 硬盘分区空间必须使用连续空间，所以硬盘分区扩容很麻烦，特别是要扩容的分区后没有空间。
- 使用硬盘分区创建的文件系统不同跨多个硬盘，受单个硬盘容量限制。
- 如果硬盘损坏，则文件系统中数据也会丢失。
逻辑卷管理硬盘方案优点
- 使用逻辑卷可以更加灵活地扩展和缩减文件系统空间。
- 使用逻辑卷创建的文件系统可以跨多个硬盘，适合创建超大容量文件系统。
- 使用逻辑卷可以创建镜像卷，保证数据的冗余性。即使单个硬盘损坏，文件系统中数据也会丢失。
- 使用逻辑卷还可以创建快照，保留某一时刻数据，就像虚拟机快照一样。
逻辑卷基本概念
LVM是 Logical Volume Manager(逻辑卷管理)的简写，LVM将若干个磁盘或者磁盘分区连接为一个整块的卷组，形成一个存储池。管理员可以在卷组上任意创建逻辑卷，并进一步在逻辑卷上创建文件系统。
- 物理卷（PV, Physical Volume），是LVM的基本存储逻辑块，通过块设备创建。块设备是指磁盘、磁盘分区或从逻辑上和磁盘分区具有同样功能的设备(如RAID)。与基本的物理存储介质（如分区、磁盘等）相比，物理卷包含有和LVM相关的管理参数。
- 卷组（VG, Volume Group），是一个逻辑的存储空间，由一个或多个物理卷组成。
- 逻辑卷（LV, Logical Volume），是从卷组中创建出来的一个逻辑空间。如果把一个卷组类比为一个逻辑硬盘，那么逻辑卷则可以类比为一个硬盘分区，所以也可以在逻辑卷之上创建文件系统。
简单地说：卷组由多个物理卷组成，可以在卷组中创建多个逻辑卷，对逻辑卷创建文件系统给用户使用。
LVM管理基本流程：
- 创建物理卷
- 创建卷组
- 创建逻辑卷
创建物理卷
# 创建单个PV
[root@server ~ 13:36:00]# pvcreate /dev/sdb
Physical volume "/dev/sdb" successfully created.
# 此次创建多个PV
[root@server ~ 13:36:22]# pvcreate /dev/sd{c,d}
Physical volume "/dev/sdc" successfully created.
Physical volume "/dev/sdd" successfully created.
# 查看PV列表
[root@server ~ 13:36:38]# pvs
PV VG Fmt Attr PSize PFree
/dev/sda2 centos lvm2 a-- <199.00g 4.00m
/dev/sdb lvm2 --- 20.00g 20.00g
/dev/sdc lvm2 --- 20.00g 20.00g
/dev/sdd lvm2 --- 20.00g 20.00g
# 查看单个PV详细信息
[root@server ~ 13:36:41]# pvdisplay /dev/sdb
"/dev/sdb" is a new physical volume of "20.00 GiB"
--- NEW Physical volume ---
PV Name /dev/sdb
VG Name
PV Size 20.00 GiB
Allocatable NO
PE Size 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID 1Kov2E-FV7J-hWP4-lZOy-Y1EP-BNAx-u69jcV
创建卷组
# 创建包涵单个PV的VG
[root@server ~ 13:37:46]# vgcreate webapp /dev/sdb
Volume group "webapp" successfully created
# 创建包涵多个PV的VG
[root@server ~ 13:38:28]# vgcreate dbapp /dev/sd{c,d}
Volume group "dbapp" successfully created
[root@server ~ 13:38:51]# pvs
PV VG Fmt Attr PSize PFree
/dev/sda2 centos lvm2 a-- <199.00g 4.00m
/dev/sdb webapp lvm2 a-- <20.00g <20.00g
/dev/sdc dbapp lvm2 a-- <20.00g <20.00g
/dev/sdd dbapp lvm2 a-- <20.00g <20.00g
# 查看VG列表
[root@server ~ 13:38:55]# vgs
VG #PV #LV #SN Attr VSize VFree
centos 1 3 0 wz--n- <199.00g 4.00m
dbapp 2 0 0 wz--n- 39.99g 39.99g
webapp 1 0 0 wz--n- <20.00g <20.00g
# 查看单个VG详细信息
[root@server ~ 13:39:42]# vgdisplay dbapp
--- Volume group ---
VG Name dbapp
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 fH4nMX-f0MZ-Y41F-1dgN-vrDD-Cile-98YDgj
创建逻辑卷
# 在卷组webapp中创建一个逻辑卷：名称为webapp01，大小为5G。
[root@server ~ 13:40:05]# lvcreate -n webapp01 -L 5G webapp
Logical volume "webapp01" created.
# 在卷组dbapp中创建一个跨硬盘逻辑卷：名称为data01，大小为25G。
[root@server ~ 13:41:08]# lvcreate -n data01 -L 25G dbapp
Logical volume "data01" created.
# 查看LV列表
[root@server ~ 13:41:25]# lvs
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
home centos -wi-ao---- <145.12g
root centos -wi-ao---- 50.00g
swap centos -wi-ao---- <3.88g
data01 dbapp -wi-a----- 25.00g
webapp01 webapp -wi-a----- 5.00g
逻辑卷设备名支持以下三种格式：
- /dev/vname/lvame
- /dev/mapper/vname-lvame
- /dev/dm-N
[root@server ~ 13:41:29]# ll /dev/dbapp/data01 /dev/mapper/dbapp-data01
lrwxrwxrwx 1 root root 7 Nov 14 13:41 /dev/dbapp/data01 -> ../dm-4
lrwxrwxrwx 1 root root 7 Nov 14 13:41 /dev/mapper/dbapp-data01 -> ../dm-4
# 查看单个LV详细信息
[root@server ~ 13:42:51]# lvdisplay /dev/dbapp/data01
--- Logical volume ---
LV Path /dev/dbapp/data01
LV Name data01
VG Name dbapp
LV UUID tcO9Ru-d73m-JZpE-oCD9-f0MM-mtqa-c0nJKQ
LV Write Access read/write
LV Creation host, time server.centos.cloud, 2025-11-14 13:41:25 +0800
LV Status available
# open 0
LV Size 25.00 GiB
Current LE 6400
Segments 2
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:4
# 可以看到：物理卷/dev/sdc空间已使用完，物理卷/dev/sdd空间已使用5G
[root@server ~ 13:43:12]# pvs
PV VG Fmt Attr PSize PFree
/dev/sda2 centos lvm2 a-- <199.00g 4.00m
/dev/sdb webapp lvm2 a-- <20.00g <15.00g
/dev/sdc dbapp lvm2 a-- <20.00g 0
/dev/sdd dbapp lvm2 a-- <20.00g 14.99g
# 可以看到逻辑卷/dev/dbapp/data01空间横跨2个硬盘
[root@server ~ 13:43:45]# lsblk /dev/sd{b..d}
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sdb 8:16 0 20G 0 disk
└─webapp-webapp01 253:3 0 5G 0 lvm
sdc 8:32 0 20G 0 disk
└─dbapp-data01 253:4 0 25G 0 lvm
sdd 8:48 0 20G 0 disk
└─dbapp-data01 253:4 0 25G 0 lvm
创建文件系统
[root@server ~ 13:44:16]# mkfs.xfs /dev/webapp/webapp01
meta-data=/dev/webapp/webapp01 isize=512 agcount=4, agsize=327680 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=0, sparse=0
data = bsize=4096 blocks=1310720, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
log =internal log bsize=4096 blocks=2560, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
[root@server ~ 13:45:56]# mkdir -p /webapp/webapp01
[root@server ~ 13:47:04]# mount /dev/webapp/webapp01 /webapp/webapp01/
# 基于lvm的文件系统持久化挂载，需要修改/etc/fstab文件。
清理
# 卸载文件系统
[root@server ~ 13:48:19]# umount /webapp/webapp01
# 删除LV
[root@server ~ 13:52:04]# lvremove /dev/webapp/webapp01 /dev/dbapp/data01
Do you really want to remove active logical volume webapp/webapp01? [y/n]: y
Logical volume "webapp01" successfully removed
Do you really want to remove active logical volume dbapp/data01? [y/n]: y
Logical volume "data01" successfully removed
# 删除VG
[root@server ~ 13:52:43]# vgremove webapp dbapp
Volume group "webapp" successfully removed
Volume group "dbapp" successfully removed
# 删除PV
[root@server ~ 13:52:53]# pvremove /dev/sd{b..d}
Labels on physical volume "/dev/sdb" successfully wiped.
Labels on physical volume "/dev/sdc" successfully wiped.
Labels on physical volume "/dev/sdd" successfully wiped.
扩展和缩减卷组
环境准备
# 创建卷组
[root@server ~ 13:53:08]# vgcreate webapp /dev/sdb
Physical volume "/dev/sdb" successfully created.
Volume group "webapp" successfully created
# 创建卷组的时候，如果指定的块设备不是物理卷，则会先将块设备创建为物理卷。
# 创建逻辑卷
[root@server ~ 14:09:27]# lvcreate -n webapp01 -L 10G webapp
WARNING: xfs signature detected on /dev/webapp/webapp01 at offset 0. Wipe it? [y/n]: y
Wiping xfs signature on /dev/webapp/webapp01.
Logical volume "webapp01" created.
扩展卷组
如果卷组空间不足，可以通过添加新的物理卷到卷组中，以扩展卷组容量。
[root@server ~ 14:09:52]# vgextend webapp /dev/sd{c,d}
Physical volume "/dev/sdc" successfully created.
Physical volume "/dev/sdd" successfully created.
Volume group "webapp" successfully extended
缩减卷组
如果卷组空间中有多余的物理卷或者物理卷容量小需要更换，则可以将物理卷从卷组中剔除。
删除物理卷前确保物理卷不在使用中。
# 查看物理卷使用状态
[root@server ~ 14:10:37]# pvs
PV VG Fmt Attr PSize PFree
/dev/sda2 centos lvm2 a-- <199.00g 4.00m
/dev/sdb webapp lvm2 a-- <20.00g <10.00g # /dev/sdb正在使用
/dev/sdc webapp lvm2 a-- <20.00g <20.00g
/dev/sdd webapp lvm2 a-- <20.00g <20.00g
# 将物理卷/dev/sdb从卷组webapp中剔除，则会报错
[root@server ~ 14:10:52]# vgreduce webapp /dev/sdb
Physical volume "/dev/sdb" still in use
# 解决方法：将物理卷/dev/sdb中数据移动到卷组中其他物理卷
[root@server ~ 14:11:58]# pvmove /dev/sdb
/dev/sdb: Moved: 0.35%
/dev/sdb: Moved: 100.00%
# 或者移动到卷组中特定物理卷
[root@centos7 ~]# pvmove /dev/sdb /dev/sdc
# 查看物理卷使用状态
[root@server ~ 14:12:56]# pvs
PV VG Fmt Attr PSize PFree
/dev/sda2 centos lvm2 a-- <199.00g 4.00m
/dev/sdb webapp lvm2 a-- <20.00g <20.00g # /dev/sdb不在使用
/dev/sdc webapp lvm2 a-- <20.00g <10.00g # /dev/sdc在使用
/dev/sdd webapp lvm2 a-- <20.00g <20.00g
# 再次剔除，成功
[root@server ~ 14:13:03]# vgreduce webapp /dev/sdb
Removed "/dev/sdb" from volume group "webapp"
[root@server ~ 14:14:22]# pvs
PV VG Fmt Attr PSize PFree
/dev/sda2 centos lvm2 a-- <199.00g 4.00m
/dev/sdb lvm2 --- 20.00g 20.00g
/dev/sdc webapp lvm2 a-- <20.00g <10.00g
/dev/sdd webapp lvm2 a-- <20.00g <20.00g
扩展和缩减逻辑卷
扩展逻辑卷
如果逻辑卷空间不足，在卷组空间充足的情况下，也可以扩展逻辑卷空间。
# 逻辑卷增加2G空间
[root@server ~ 14:14:31]# lvextend -L +2G /dev/webapp/webapp01
Size of logical volume webapp/webapp01 changed from 10.00 GiB (2560 extents) to 12.00 GiB (3072 extents).
Logical volume webapp/webapp01 successfully resized.
[root@server ~ 14:15:05]# lvs /dev/webapp/webapp01
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
webapp01 webapp -wi-a----- 12.00g
缩减逻辑卷
如果逻辑卷空间充足，希望将多余的空间缩减出来它用，也可以缩减逻辑卷空间。
[root@server ~ 14:15:16]# lvreduce -L -2G /dev/webapp/webapp01
WARNING: Reducing active logical volume to 10.00 GiB.
THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce webapp/webapp01? [y/n]: y
Size of logical volume webapp/webapp01 changed from 12.00 GiB (3072 extents) to 10.00 GiB (2560 extents).
Logical volume webapp/webapp01 successfully resized.
[root@server ~ 14:15:58]# lvs /dev/webapp/webapp01
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
webapp01 webapp -wi-a----- 10.00g
扩展和缩减文件系统
扩展 XFS 文件系统
XFS文件系统只支持扩展，不支持缩减。
环境准备：格式化文件系统，并创建数据
[root@server ~ 14:49:17]# mkfs.xfs /dev/webapp/webapp01 meta-data=/dev/webapp/webapp01 isize=512 agcount=4, agsize=655360 blks = sectsz=512 attr=2, projid32bit=1 = crc=1 finobt=0, sparse=0 data = bsize=4096 blocks=2621440, imaxpct=25 = sunit=0 swidth=0 blks naming =version 2 bsize=4096 ascii-ci=0 ftype=1 log =internal log bsize=4096 blocks=2560, version=2 = sectsz=512 sunit=0 blks, lazy-count=1 realtime =none extsz=4096 blocks=0, rtextents=0 [root@server ~ 14:49:37]# mkdir /var/www/html/ [root@server ~ 14:49:51]# mount /dev/webapp/webapp01 /var/www/html/ [root@server ~ 14:50:08]# cp /etc/host* /var/www/html/ [root@server ~ 14:50:25]# ls /var/www/html/ host.conf hostname hosts hosts.allow hosts.deny
# 第一步：扩展逻辑卷
[root@server ~ 14:51:05]# lvextend -L 15G /dev/webapp/webapp01
Size of logical volume webapp/webapp01 changed from 10.00 GiB (2560 extents) to 15.00 GiB (3840 extents).
Logical volume webapp/webapp01 successfully resized.
[root@server ~ 14:53:11]# lvs /dev/webapp/webapp01
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
webapp01 webapp -wi-ao---- 15.00g
# 第二步：扩展文件系统
[root@server ~ 14:53:20]# xfs_growfs /var/www/html/
meta-data=/dev/mapper/webapp-webapp01 isize=512 agcount=4, agsize=655360 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=0 spinodes=0
data = bsize=4096 blocks=2621440, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
log =internal bsize=4096 blocks=2560, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
data blocks changed from 2621440 to 3932160
[root@server ~ 14:53:51]# df -h /var/www/html/
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/webapp-webapp01 15G 33M 15G 1% /var/www/html
[root@server ~ 14:53:57]# ls /var/www/html/
host.conf hostname hosts hosts.allow hosts.deny
# 块设备和文件系统一并扩展
[root@server ~ 14:54:05]# lvextend -rL 20G /dev/webapp/webapp01
Size of logical volume webapp/webapp01 changed from 15.00 GiB (3840 extents) to 20.00 GiB (5120 extents).
Logical volume webapp/webapp01 successfully resized.
meta-data=/dev/mapper/webapp-webapp01 isize=512 agcount=6, agsize=655360 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=0 spinodes=0
data = bsize=4096 blocks=3932160, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
log =internal bsize=4096 blocks=2560, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
data blocks changed from 3932160 to 5242880
[root@server ~ 14:54:50]# lvs /dev/webapp/webapp01
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
webapp01 webapp -wi-ao---- 20.00g
[root@server ~ 14:55:38]# df -Th /var/www/html/
Filesystem Type Size Used Avail Use% Mounted on
/dev/mapper/webapp-webapp01 xfs 20G 33M 20G 1% /var/www/html
扩展 EXT4 文件系统
EXT4文件系统即支持扩展，也支持缩减。
环境准备：格式化文件系统，并创建数据
[root@server ~ 14:55:51]# umount /var/www/html [root@server ~ 14:56:13]# mkfs.ext4 /dev/webapp/webapp01 mke2fs 1.42.9 (28-Dec-2013) Filesystem label= OS type: Linux Block size=4096 (log=2) Fragment size=4096 (log=2) Stride=0 blocks, Stripe width=0 blocks 1310720 inodes, 5242880 blocks 262144 blocks (5.00%) reserved for the super user First data block=0 Maximum filesystem blocks=2153775104 160 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 Allocating group tables: done Writing inode tables: done Creating journal (32768 blocks): done Writing superblocks and filesystem accounting information: done [root@server ~ 14:56:27]# mount /dev/webapp/webapp01 /var/www/html/ [root@server ~ 14:57:22]# df -Th /var/www/html/ Filesystem Type Size Used Avail Use% Mounted on /dev/mapper/webapp-webapp01 ext4 20G 45M 19G 1% /var/www/html [root@server ~ 14:57:29]# cp /etc/host* /var/www/html/ [root@server ~ 14:58:04]# ls /var/www/html/ host.conf hostname hosts hosts.allow hosts.deny
# 第一步：扩展逻辑卷
[root@server ~ 14:58:10]# lvextend -L 25G /dev/webapp/webapp01
Size of logical volume webapp/webapp01 changed from 20.00 GiB (5120 extents) to 25.00 GiB (6400 extents).
Logical volume webapp/webapp01 successfully resized.
[root@server ~ 14:58:42]# lvs /dev/webapp/webapp01
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
webapp01 webapp -wi-ao---- 25.00g
# 第二步：扩展文件系统
[root@server ~ 14:58:48]# resize2fs /dev/webapp/webapp01
resize2fs 1.42.9 (28-Dec-2013)
Filesystem at /dev/webapp/webapp01 is mounted on /var/www/html; on-line resizing required
old_desc_blocks = 3, new_desc_blocks = 4
The filesystem on /dev/webapp/webapp01 is now 6553600 blocks long.
[root@server ~ 14:59:10]# df -Th /var/www/html/
Filesystem Type Size Used Avail Use% Mounted on
/dev/mapper/webapp-webapp01 ext4 25G 44M 24G 1% /var/www/html
[root@server ~ 14:59:17]# ls /var/www/html/
host.conf hostname hosts hosts.allow hosts.deny
# 块设备和文件系统一并扩展
[root@server ~ 14:59:25]# lvextend -rL 30G /dev/webapp/webapp01
Size of logical volume webapp/webapp01 changed from 25.00 GiB (6400 extents) to 30.00 GiB (7680 extents).
Logical volume webapp/webapp01 successfully resized.
resize2fs 1.42.9 (28-Dec-2013)
Filesystem at /dev/mapper/webapp-webapp01 is mounted on /var/www/html; on-line resizing required
old_desc_blocks = 4, new_desc_blocks = 4
The filesystem on /dev/mapper/webapp-webapp01 is now 7864320 blocks long.
[root@server ~ 15:00:01]# lvs /dev/webapp/webapp01
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
webapp01 webapp -wi-ao---- 30.00g
[root@server ~ 15:00:51]# df -Th /var/www/html/
Filesystem Type Size Used Avail Use% Mounted on
/dev/mapper/webapp-webapp01 ext4 30G 44M 28G 1% /var/www/html
缩减 EXT4 文件系统
缩减EXT4文件系统注意事项：
- 不支持在线缩减，必须卸载后缩减。
- 缩减后的容量，不能小于当前使用的容量。
ext4 减容流程：
- 卸载文件系统
- e2fsck 文件系统
- 缩减文件系统
- 缩减lv
- 挂载测试
具体操作如下：
# 第一步：卸载文件系统
[root@server ~ 15:00:59]# umount /var/www/html
# 第二步：检测文件系统
[root@server ~ 15:01:27]# e2fsck -f /dev/webapp/webapp01
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/webapp/webapp01: 16/1966080 files (0.0% non-contiguous), 167447/7864320 blocks
# 第三步：缩减文件系统
[root@server ~ 15:01:39]# resize2fs /dev/webapp/webapp01 10G
resize2fs 1.42.9 (28-Dec-2013)
Resizing the filesystem on /dev/webapp/webapp01 to 2621440 (4k) blocks.
The filesystem on /dev/webapp/webapp01 is now 2621440 blocks long.
# 第四步：缩减逻辑卷
[root@server ~ 15:02:13]# lvreduce -L 10G /dev/webapp/webapp01
WARNING: Reducing active logical volume to 10.00 GiB.
THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce webapp/webapp01? [y/n]: y
Size of logical volume webapp/webapp01 changed from 30.00 GiB (7680 extents) to 10.00 GiB (2560 extents).
Logical volume webapp/webapp01 successfully resized.
# 第五步：挂载文件系统验证
[root@centos7 ~]# mount /dev/webapp/webapp01 /var/www/html
[root@server ~ 15:04:33]# mount /dev/webapp/webapp01 /var/www/html/
[root@server ~ 15:05:01]# df -Th /var/www/html/
Filesystem Type Size Used Avail Use% Mounted on
/dev/mapper/webapp-webapp01 ext4 9.8G 37M 9.2G 1% /var/www/html
[root@server ~ 15:05:09]# ls /var/www/html/
host.conf hostname hosts hosts.allow hosts.deny lost+found
补充说明： 如果文件系统是构建在磁盘分区上，扩展文件系统容量和缩减文件系统容量操作相同。
练习：缩减/home磁盘空间100G给/使用
- 备份 home
- 卸载
- 缩减 /dev/mapper/centos-home 100G
- 格式化 /dev/mapper/centos-home xfs
- 恢复home的数据
- /dev/mapper/centos-root 扩容100
[root@client ~ 15:38:09]# xfsdump -L "Home Directory Backup" -M "Backup_Drive_20241114" -f /tmp/home_backup_full.dump /home
xfsdump: using file dump (drive_simple) strategy
xfsdump: version 3.1.7 (dump format 3.0) - type ^C for status and control
xfsdump: level 0 dump of client.centos.cloud:/home
xfsdump: dump date: Fri Nov 14 15:38:12 2025
xfsdump: session id: 1aa610d6-3ff1-4dc0-9bfc-bc3924e1b1f2
xfsdump: session label: "Home Directory Backup"
xfsdump: ino map phase 1: constructing initial dump list
xfsdump: ino map phase 2: skipping (no pruning necessary)
xfsdump: ino map phase 3: skipping (only one dump stream)
xfsdump: ino map construction complete
xfsdump: estimated dump size: 34368 bytes
xfsdump: /var/lib/xfsdump/inventory created
xfsdump: creating dump session media file 0 (media 0, file 0)
xfsdump: dumping ino map
xfsdump: dumping directories
xfsdump: dumping non-directory files
xfsdump: ending media file
xfsdump: media file size 25608 bytes
xfsdump: dump size (non-dir files) : 1632 bytes
xfsdump: dump complete: 0 seconds elapsed
xfsdump: Dump Summary:
xfsdump: stream 0 /tmp/home_backup_full.dump OK (success)
xfsdump: Dump Status: SUCCESS
[root@client ~ 15:39:13]# umount /home
[root@client ~ 15:39:21]# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 200G 0 disk
├─sda1 8:1 0 1G 0 part /boot
└─sda2 8:2 0 199G 0 part
├─centos-root 253:0 0 50G 0 lvm /
├─centos-swap 253:1 0 3.9G 0 lvm [SWAP]
└─centos-home 253:2 0 145.1G 0 lvm
sr0 11:0 1 4.4G 0 rom
[root@client ~ 15:39:25]# lvreduce -L 100G /dev/centos/home
WARNING: Reducing active logical volume to 100.00 GiB.
THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce centos/home? [y/n]: y
Size of logical volume centos/home changed from <145.12 GiB (37150 extents) to 100.00 GiB (25600 extents).
Logical volume centos/home successfully resized.
[root@client ~ 15:44:30]# lvreduce -L 50G /dev/centos/home
WARNING: Reducing active logical volume to 50.00 GiB.
THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce centos/home? [y/n]: y
Size of logical volume centos/home changed from 100.00 GiB (25600 extents) to 50.00 GiB (12800 extents).
Logical volume centos/home successfully resized.
[root@client ~ 15:44:51]# mkfs.xfs -f /dev/centos/home
meta-data=/dev/centos/home isize=512 agcount=4, agsize=3276800 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=0, sparse=0
data = bsize=4096 blocks=13107200, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
log =internal log bsize=4096 blocks=6400, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
[root@client ~ 15:46:27]# mount /dev/centos/home /home/
[root@client ~ 15:46:32]# xfsrestore -f /tmp/home_backup_full.dump /home/
xfsrestore: using file dump (drive_simple) strategy
xfsrestore: version 3.1.7 (dump format 3.0) - type ^C for status and control
xfsrestore: searching media for dump
xfsrestore: examining media file 0
xfsrestore: dump description:
xfsrestore: hostname: client.centos.cloud
xfsrestore: mount point: /home
xfsrestore: volume: /dev/mapper/centos-home
xfsrestore: session time: Fri Nov 14 15:38:12 2025
xfsrestore: level: 0
xfsrestore: session label: "Home Directory Backup"
xfsrestore: media label: "Backup_Drive_20241114"
xfsrestore: file system id: c266ce41-65ca-4780-a0c5-0a771c38b850
xfsrestore: session id: 1aa610d6-3ff1-4dc0-9bfc-bc3924e1b1f2
xfsrestore: media id: 53196597-8bc1-42fa-9cf4-fe51ee4f226e
xfsrestore: using online session inventory
xfsrestore: searching media for directory dump
xfsrestore: reading directories
xfsrestore: 2 directories and 4 entries processed
xfsrestore: directory post-processing
xfsrestore: restoring non-directory files
xfsrestore: restore complete: 0 seconds elapsed
xfsrestore: Restore Summary:
xfsrestore: stream 0 /tmp/home_backup_full.dump OK (success)
xfsrestore: Restore Status: SUCCESS
[root@client ~ 15:50:52]# lvextend -r -l +100%FREE /dev/centos/root
Size of logical volume centos/root changed from 50.00 GiB (12800 extents) to 145.12 GiB (37151 extents).
Logical volume centos/root successfully resized.
meta-data=/dev/mapper/centos-root isize=512 agcount=4, agsize=3276800 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=0 spinodes=0
data = bsize=4096 blocks=13107200, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
log =internal bsize=4096 blocks=6400, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
data blocks changed from 13107200 to 38042624
[root@client ~ 15:51:04]# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 200G 0 disk
├─sda1 8:1 0 1G 0 part /boot
└─sda2 8:2 0 199G 0 part
├─centos-root 253:0 0 145.1G 0 lvm /
├─centos-swap 253:1 0 3.9G 0 lvm [SWAP]
└─centos-home 253:2 0 50G 0 lvm /home
sr0 11:0 1 4.4G 0 rom
逻辑卷快照
我们可以使用快照记录了lv中数据，后续可以用来恢复数据。
# 创建快照：快照的容量不能小于lv容量
[root@centos7 ~]# lvcreate -s -n webapp01-snap1 -L 10G /dev/webapp/webapp01
Logical volume "webapp01-snap1" created.
# 挂载快照
[root@centos7 ~]# mount /dev/webapp/webapp01-snap1 /webapp/webapp01/
# 查看数据
[root@centos7 ~]# ls /webapp/webapp01/
host.conf hostname hosts hosts.allow hosts.deny
# 创建新数据
[root@centos7 ~]# echo hello world > /webapp/webapp01/hello.txt
[root@centos7 ~]# cat /webapp/webapp01/hello.txt
hello world
raid 逻辑卷
准备环境
[root@centos7 ~]# umount /webapp/webapp0
[root@centos7 ~]# umount /var/www/html
[root@centos7 ~]# lvremove /dev/webapp/webapp01*
创建 raid1 逻辑卷
[root@centos7 ~]# lvcreate --type raid1 -n webapp01 -L 15G webapp
[root@centos7 ~]# mkfs.xfs /dev/webapp/webapp01
[root@centos7 ~]# mount /dev/webapp/webapp01 /var/www/html/
[root@centos7 ~]# cp /etc/ho* /var/www/html/
模拟故障
[root@centos7 ~]# dd if=/dev/zero of=/dev/sdd bs=1M count=256
此时文件系统仍可以正方访问
[root@centos7 ~]# ls /var/www/html/
host.conf hostname hosts hosts.allow hosts.deny
[root@centos7 ~]# umount /var/www/html
[root@centos7 ~]# mount /dev/webapp/webapp01 /var/www/html/
修复raid
# 删除丢失的物理卷
[root@centos7 ~]# vgreduce --removemissing webapp --force
# 扩容回来
[root@centos7 ~]# vgextend webapp /dev/sdd
# 修复raid1 逻辑卷
[root@centos7 ~]# lvconvert --repair /dev/webapp/webapp01
# 扫描物理卷变化
[root@centos7 ~]# pvscan
# 验证结果
[root@centos7 ~]# pvs|grep webap
/dev/sdb webapp lvm2 a-- <20.00g 4.99g
/dev/sdc webapp lvm2 a-- <20.00g 4.99g
/dev/sdd webapp lvm2 a-- <20.00g <20.00g
其他示例：创建 raid5 逻辑卷
# Create a RAID5 LV with a usable size of 5GiB, 3 stripes, a stripe size of 64KiB, using a total of 4 devices (including one for parity).
lvcreate --type raid5 -L 5G -i 3 -I 64 -n mylv vg00
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