运维之基础命令--逻辑卷管理
一、LVM介绍
逻辑卷管理LVM是一个多才多艺的硬盘系统工具。无论在Linux或者其他类似的系统，都是非常的好用。传统分区使用固定大小分区，重新调整大小十分麻烦。但是，LVM可以创建和管理“逻辑”卷，而不是直接使用物理硬盘。可以让管理员弹性的管理逻辑卷的扩大缩小，操作简单，而不损坏已存储的数据。可以随意将新的硬盘添加到LVM，以直接扩展已经存在的逻辑卷。LVM并不需要重启就可以让内核知道分区的存在。
LVM使用分层结构，如下如所示：
图中顶部，首先是实际的物理磁盘及其划分的分区和其上的物理卷（PV）。一个或多个物理卷可以用来创建卷组（VG）。然后基于卷组可以创建逻辑卷（LV）。只要在卷组中有可用空间，就可以随心所欲的创建逻辑卷。文件系统就是在逻辑卷上创建的，然后可以在操作系统挂载和访问
二、LVM使用
2.1 磁盘准备
加装两块硬盘，sdb-10G与sdc-5G
[root@lb01 ~]# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 50G 0 disk
├─sda1 8:1 0 1G 0 part /boot
├─sda2 8:2 0 2G 0 part [SWAP]
└─sda3 8:3 0 47G 0 part /
sdb 8:16 0 10G 0 disk
sdc 8:32 0 5G 0 disk
sr0 11:0 1 792M 0 rom给sbd创建LVM分区
[root@lb01 ~]# 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.
Command (m for help): n # 新建分区
Partition type:
p primary (0 primary, 0 extended, 4 free)
e extended
Select (default p):
Using default response 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): +2G
Partition 1 of type Linux and of size 2 GiB is set
Command (m for help): t # 将分区改为LVM分区
Selected partition 1
Hex code (type L to list all codes): L
0 Empty 24 NEC DOS 81 Minix / old Lin bf Solaris
1 FAT12 27 Hidden NTFS Win 82 Linux swap / So c1 DRDOS/sec (FAT-
2 XENIX root 39 Plan 9 83 Linux c4 DRDOS/sec (FAT-
3 XENIX usr 3c PartitionMagic 84 OS/2 hidden C: c6 DRDOS/sec (FAT-
4 FAT16 <32M 40 Venix 80286 85 Linux extended c7 Syrinx
5 Extended 41 PPC PReP Boot 86 NTFS volume set da Non-FS data
6 FAT16 42 SFS 87 NTFS volume set db CP/M / CTOS / .
7 HPFS/NTFS/exFAT 4d QNX4.x 88 Linux plaintext de Dell Utility
8 AIX 4e QNX4.x 2nd part 8e Linux LVM df BootIt
9 AIX bootable 4f QNX4.x 3rd part 93 Amoeba e1 DOS access
a OS/2 Boot Manag 50 OnTrack DM 94 Amoeba BBT e3 DOS R/O
b W95 FAT32 51 OnTrack DM6 Aux 9f BSD/OS e4 SpeedStor
c W95 FAT32 (LBA) 52 CP/M a0 IBM Thinkpad hi eb BeOS fs
e W95 FAT16 (LBA) 53 OnTrack DM6 Aux a5 FreeBSD ee GPT
f W95 Ext'd (LBA) 54 OnTrackDM6 a6 OpenBSD ef EFI (FAT-12/16/
10 OPUS 55 EZ-Drive a7 NeXTSTEP f0 Linux/PA-RISC b
11 Hidden FAT12 56 Golden Bow a8 Darwin UFS f1 SpeedStor
12 Compaq diagnost 5c Priam Edisk a9 NetBSD f4 SpeedStor
14 Hidden FAT16 <3 61 SpeedStor ab Darwin boot f2 DOS secondary
16 Hidden FAT16 63 GNU HURD or Sys af HFS / HFS+ fb VMware VMFS
17 Hidden HPFS/NTF 64 Novell Netware b7 BSDI fs fc VMware VMKCORE
18 AST SmartSleep 65 Novell Netware b8 BSDI swap fd Linux raid auto
1b Hidden W95 FAT3 70 DiskSecure Mult bb Boot Wizard hid fe LANstep
1c Hidden W95 FAT3 75 PC/IX be Solaris boot ff BBT
1e Hidden W95 FAT1 80 Old Minix
Hex code (type L to list all codes): 8e
Changed type of partition 'Linux' to 'Linux LVM'
Command (m for help): p
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: 0x0005122b
Device Boot Start End Blocks Id System
/dev/sdb1 2048 4196351 2097152 8e Linux LVM重复添加，再加一个3G，一个2G的分区，可见分区表如下：
[root@lb01 ~]# fdisk -l /dev/sdb
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: 0x0005122b
Device Boot Start End Blocks Id System
/dev/sdb1 2048 4196351 2097152 8e Linux LVM
/dev/sdb2 4196352 10487807 3145728 8e Linux LVM
/dev/sdb3 10487808 14682111 2097152 8e Linux LVM2.2 创建物理卷（PV）
安装LVM工具
[root@lb01 ~]# yum install lvm2 将准备好的LVM分区生成为物理卷
[root@lb01 ~]# pvcreate /dev/sdb1
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.
[root@lb01 ~]# pvcreate /dev/sdb2
Physical volume "/dev/sdb2" successfully created.
[root@lb01 ~]# pvcreate /dev/sdb3
Physical volume "/dev/sdb3" successfully created.查看物理卷信息
[root@lb01 ~]# pvdisplay
"/dev/sdb1" is a new physical volume of "2.00 GiB"
--- NEW Physical volume ---
PV Name /dev/sdb1
VG Name
PV Size 2.00 GiB
Allocatable NO
PE Size 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID YUHdrd-AH1x-ew0m-Mp9i-3GHp-S4zc-XxlDJM
"/dev/sdb2" is a new physical volume of "3.00 GiB"
--- NEW Physical volume ---
PV Name /dev/sdb2
VG Name
PV Size 3.00 GiB
Allocatable NO
PE Size 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID wGDQvx-7zfs-g018-wqx4-Y8rh-1kWT-PnLuFu
"/dev/sdb3" is a new physical volume of "2.00 GiB"
--- NEW Physical volume ---
PV Name /dev/sdb3
VG Name
PV Size 2.00 GiB
Allocatable NO
PE Size 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID fykcuR-jooY-WKbi-yM8j-7fQ5-mhnH-JCkXC8补充：如何删除物理卷
[root@lb01 ~]# pvremove /dev/sdb12.3 创建卷组（VG）
将/dev/sdb{1,2,3}合并为卷组vg01
[root@lb01 ~]# vgcreate vg01 /dev/sdb1 /dev/sdb2 /dev/sdb3查看卷组信息
[root@lb01 ~]# vgdisplay
--- Volume group ---
VG Name vg01
System ID
Format lvm2
Metadata Areas 3
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 3
Act PV 3
VG Size <6.99 GiB
PE Size 4.00 MiB
Total PE 1789
Alloc PE / Size 0 / 0
Free PE / Size 1789 / <6.99 GiB
VG UUID gzeouH-16qO-n6xv-V6VM-A9ep-eK6E-ODuIwU补充：如何删除卷组
[root@lb01 ~]# vgremove vg01
Volume group "vg01" successfully removed2.4 创建逻辑卷（LV）
创建一个名为lv01，大小为100M的逻辑卷
[root@lb01 ~]# lvcreate -L 100M -n lv01 vg01
Logical volume "lv01" created.查看逻辑卷
[root@lb01 ~]# lvdisplay
--- Logical volume ---
LV Path /dev/vg01/lv01
LV Name lv01
VG Name vg01
LV UUID xFksnb-ENc2-mEo4-5gEb-yaJj-wP2c-oFuBeT
LV Write Access read/write
LV Creation host, time lb01, 2021-09-01 20:39:16 +0800
LV Status available
# open 0
LV Size 100.00 MiB
Current LE 25
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:0补充：删除逻辑卷
[root@lb01 ~]# lvremove /dev/vg01/lv02
Do you really want to remove active logical volume vg01/lv02? [y/n]: y
Logical volume "lv02" successfully removed2.5 逻辑卷挂载
格式化逻辑卷
[root@lb01 ~]# mkfs.ext4 /dev/vg01/lv01
mke2fs 1.42.9 (28-Dec-2013)
Filesystem label=
OS type: Linux
Block size=1024 (log=0)
Fragment size=1024 (log=0)
Stride=0 blocks, Stripe width=0 blocks
25688 inodes, 102400 blocks
5120 blocks (5.00%) reserved for the super user
First data block=1
Maximum filesystem blocks=33685504
13 block groups
8192 blocks per group, 8192 fragments per group
1976 inodes per group
Superblock backups stored on blocks:
8193, 24577, 40961, 57345, 73729
Allocating group tables: done
Writing inode tables: done
Creating journal (4096 blocks): done
Writing superblocks and filesystem accounting information: done挂载逻辑卷
[root@lb01 ~]# mkdir /mnt/test-lv01
[root@lb01 ~]# mount /dev/vg01/lv01 /mnt/test-lv01
[root@lb01 ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda3 47G 1.9G 46G 4% /
devtmpfs 479M 0 479M 0% /dev
tmpfs 489M 0 489M 0% /dev/shm
tmpfs 489M 6.8M 482M 2% /run
tmpfs 489M 0 489M 0% /sys/fs/cgroup
/dev/sda1 1014M 119M 896M 12% /boot
tmpfs 98M 0 98M 0% /run/user/0
/dev/mapper/vg01-lv01 93M 1.6M 85M 2% /mnt/test-lv012.6 扩展逻辑卷
卸载逻辑卷
[root@lb01 ~]# umount /dev/vg01/lv01将逻辑卷lv01调整为200M
[root@lb01 ~]# lvresize -L 200M /dev/vg01/lv01
Size of logical volume vg01/lv01 changed from 100.00 MiB (25 extents) to 200.00 MiB (50 extents).
Logical volume vg01/lv01 successfully resized.检查磁盘错误
[root@lb01 ~]# e2fsck -f /dev/vg01/lv01
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/vg01/lv01: 11/25688 files (9.1% non-contiguous), 8896/102400 blocks调整文件系统大小
[root@lb01 ~]# resize2fs /dev/vg01/lv01查看逻辑卷信息
[root@lb01 ~]# lvdisplay
--- Logical volume ---
LV Path /dev/vg01/lv01
LV Name lv01
VG Name vg01
LV UUID svm5Xk-B8jZ-QhZw-egCm-x6b2-e5Jt-wvMi2F
LV Write Access read/write
LV Creation host, time lb01, 2021-09-01 20:41:53 +0800
LV Status available
# open 0
LV Size 200.00 MiB
Current LE 50
Segments 2
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:0
...重新挂载使用
[root@lb01 ~]# !mount
mount /dev/vg01/lv01 /mnt/test-lv01
[root@lb01 ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda3 47G 1.9G 46G 4% /
devtmpfs 479M 0 479M 0% /dev
tmpfs 489M 0 489M 0% /dev/shm
tmpfs 489M 6.8M 482M 2% /run
tmpfs 489M 0 489M 0% /sys/fs/cgroup
/dev/sda1 1014M 119M 896M 12% /boot
tmpfs 98M 0 98M 0% /run/user/0
/dev/mapper/vg01-lv01 190M 1.6M 175M 1% /mnt/test-lv012.7 缩减逻辑卷
卸载逻辑卷
[root@lb01 ~]# umount /dev/vg01/lv01检查磁盘错误
[root@lb01 ~]# e2fsck -f /dev/vg01/lv01
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/vg01/lv01: 11/49400 files (9.1% non-contiguous), 11884/204800 blocks缩减文件系统大小，更新ext4信息
[root@lb01 ~]# resize2fs /dev/vg01/lv01 100M
resize2fs 1.42.9 (28-Dec-2013)
Resizing the filesystem on /dev/vg01/lv01 to 102400 (1k) blocks.
The filesystem on /dev/vg01/lv01 is now 102400 blocks long.完成后，减小逻辑卷大小
[root@lb01 ~]# lvresize -L 100M /dev/vg01/lv01
WARNING: Reducing active logical volume to 100.00 MiB.
THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce vg01/lv01? [y/n]: y
Size of logical volume vg01/lv01 changed from 200.00 MiB (50 extents) to 100.00 MiB (25 extents).
Logical volume vg01/lv01 successfully resized.查看逻辑卷信息
[root@lb01 ~]# lvdisplay
--- Logical volume ---
LV Path /dev/vg01/lv01
LV Name lv01
VG Name vg01
LV UUID svm5Xk-B8jZ-QhZw-egCm-x6b2-e5Jt-wvMi2F
LV Write Access read/write
LV Creation host, time lb01, 2021-09-01 20:41:53 +0800
LV Status available
# open 0
LV Size 100.00 MiB
Current LE 25
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:0
...挂载使用
[root@lb01 ~]# !mo
mount /dev/vg01/lv01 /mnt/test-lv01
[root@lb01 ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda3 47G 1.9G 46G 4% /
devtmpfs 479M 0 479M 0% /dev
tmpfs 489M 0 489M 0% /dev/shm
tmpfs 489M 6.8M 482M 2% /run
tmpfs 489M 0 489M 0% /sys/fs/cgroup
/dev/sda1 1014M 119M 896M 12% /boot
tmpfs 98M 0 98M 0% /run/user/0
/dev/mapper/vg01-lv01 93M 1.6M 85M 2% /mnt/test-lv012.8 VG增加一块磁盘
新盘创建lvm分区
[root@lb01 ~]# 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 0x05ff27fa.
Command (m for help): n
Partition type:
p primary (0 primary, 0 extended, 4 free)
e extended
Select (default p):
Using default response p
Partition number (1-4, default 1):
First sector (2048-10485759, default 2048):
Using default value 2048
Last sector, +sectors or +size{K,M,G} (2048-10485759, default 10485759): +4G
Partition 1 of type Linux and of size 4 GiB is set
Command (m for help): t
Selected partition 1
Hex code (type L to list all codes):
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: 5368 MB, 5368709120 bytes, 10485760 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: 0x05ff27fa
Device Boot Start End Blocks Id System
/dev/sdc1 2048 8390655 4194304 8e Linux LVM创建物理卷
[root@lb01 ~]# pvcreate /dev/sdc1
Physical volume "/dev/sdc1" successfully created.扩容VG
[root@lb01 ~]# vgextend vg01 /dev/sdc1
Volume group "vg01" successfully extended查看VG信息
[root@lb01 ~]# vgdisplay vg01
--- Volume group ---
VG Name vg01
System ID
Format lvm2
Metadata Areas 4
Metadata Sequence No 10
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 2
Open LV 1
Max PV 0
Cur PV 4
Act PV 4
VG Size 10.98 GiB
PE Size 4.00 MiB
Total PE 2812
Alloc PE / Size 50 / 200.00 MiB
Free PE / Size 2762 / <10.79 GiB
VG UUID 2Tjzna-XmXI-9MQ7-zeyc-AARV-84r5-jyymkfPS：尽管我们使用一个单独的磁盘做示范，其实只要是‘8e’类型的磁盘分区都可以用来扩展卷组。
在VG中创建LV，可以看到磁盘都用上了
[root@lb01 ~]# lvcreate -L 10G -n lv03 vg01
Logical volume "lv03" created.
[root@lb01 ~]# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 50G 0 disk
├─sda1 8:1 0 1G 0 part /boot
├─sda2 8:2 0 2G 0 part [SWAP]
└─sda3 8:3 0 47G 0 part /
sdb 8:16 0 10G 0 disk
├─sdb1 8:17 0 2G 0 part
│ ├─vg01-lv01 253:0 0 100M 0 lvm /mnt/test-lv01
│ ├─vg01-lv02 253:1 0 100M 0 lvm
│ └─vg01-lv03 253:2 0 10G 0 lvm
├─sdb2 8:18 0 3G 0 part
│ └─vg01-lv03 253:2 0 10G 0 lvm
└─sdb3 8:19 0 2G 0 part
└─vg01-lv03 253:2 0 10G 0 lvm
sdc 8:32 0 5G 0 disk
└─sdc1 8:33 0 4G 0 part
└─vg01-lv03 253:2 0 10G 0 lvm
sr0 11:0 1 792M 0 rom运维之基础命令--逻辑卷管理
http://gsproj.github.io/2022/07/06/01_运维/01-基础命令/day19-磁盘分区/02_逻辑卷管理/