简介
LVM 是逻辑盘卷管理（LogicalVolumeManager）的简称，在 Linux 环境下对磁盘分区进行管理的一种机制，LVM 是建立在硬盘和 分区之上的一个逻辑层，来提高磁盘分区管理的灵活性。通过 LVM 系统管理员可以轻松管理磁盘分区，如：将若干个磁盘分区连接为一个整块的卷（volumegroup），形成一个存储池。管理员可以在卷组上随意创建逻辑卷组（logicalvolumes），并进一步在逻辑卷组上创建文件系统。
LVM 组成
Logical Volume Manager(逻辑卷管理）
PV:是物理的磁盘分区
VG:LVM 中的物理的磁盘分区，也就是 PV，必须加入 VG，可以将 VG 理解为一个仓库统一管理了几个大的硬盘，形成了一个统一虚拟的存储资源池。
LV：也就是从 VG 中划分的逻辑分区
LVM 模型
操作环境介绍
1，在线扩容根分区，根分区 100G，新增一块 20G 硬盘，将根分区扩容至 120G。
2，新建逻辑卷并扩容和缩减，新增 2 块 20G 磁盘，划分 10GLV，再扩容 10G，随后缩减 5G.
扩容根分区
查看系统可用块设备以及依赖关系
[root@zabbix-server ~]# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 100G 0 disk
├─sda1 8:1 0 500M 0 part /boot
└─sda2 8:2 0 99G 0 part
├─centos-root 253:0 0 91G 0 lvm /
└─centos-swap 253:1 0 8G 0 lvm [SWAP]
sdb 8:16 0 20G 0 disk
sr0 11:0 1 4.3G 0 rom
查看系统初始硬盘
[root@zabbix-server ~]# df -hT
Filesystem Type Size Used Avail Use% Mounted on
/dev/mapper/centos-root xfs 91G 1.6G 90G 2% /
devtmpfs devtmpfs 1.9G 0 1.9G 0% /dev
tmpfs tmpfs 1.9G 0 1.9G 0% /dev/shm
tmpfs tmpfs 1.9G 12M 1.9G 1% /run
tmpfs tmpfs 1.9G 0 1.9G 0% /sys/fs/cgroup
/dev/sda1 xfs 497M 139M 359M 28% /boot
tmpfs tmpfs 378M 0 378M 0% /run/user/0
查看当前物理卷
[root@zabbix-server ~]# pvs
PV VG Fmt Attr PSize PFree
/dev/sda2 centos lvm2 a-- 99.00g 0
创建硬盘分区
[root@zabbix-server ~]# 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 0x6488a7cc.
Command (m for help): n //添加新分区
Partition type:
p primary (0 primary, 0 extended, 4 free)
e extended
Select (default p): p // 回车，默认p，主分区
Partition number (1-4, default 1): // 回车，默认1
First sector (2048-41943039, default 2048): // 回车，默认起始位置
Using default value 2048
Last sector, +sectors or +size{K,M,G} (2048-41943039, default 41943039): // 回车，默认最后位置
Using default value 41943039
Partition 1 of type Linux and of size 20 GiB is set
Command (m for help): t // 更改分区格式
Selected partition 1
Hex code (type L to list all codes): L // 查看可选项
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 // 更改分区格式为LVM
Changed type of partition 'Linux' to 'Linux LVM'
Command (m for help): p //打印，Blocks为分区大小 单位为kb
Disk /dev/sdb: 21.5 GB, 21474836480 bytes, 41943040 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: 0x6488a7cc
Device Boot Start End Blocks Id System
/dev/sdb1 2048 41943039 20970496 8e Linux LVM
Command (m for help): w //保存
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
将物理硬盘格式化成 PV（物理卷） 使用的是 pvcreate 命令
[root@zabbix-server ~]# pvcreate /dev/sdb1
Physical volume "/dev/sdb1" successfully created.
查看当前 vg 信息
[root@zabbix-server ~]# vgdisplay
--- Volume group ---
VG Name centos
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 3
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 2
Open LV 2
Max PV 0
Cur PV 1
Act PV 1
VG Size 99.00 GiB
PE Size 4.00 MiB
Total PE 25344
Alloc PE / Size 25344 / 99.00 GiB
Free PE / Size 0 / 0
VG UUID 280QHe-8dkW-t34f-9JKh-QhMk-1rZE-cejqal
把转换好的物理卷并到 vg（卷组）中， 通过 vgcreate 命令
[root@zabbix-server ~]# vgextend centos /dev/sdb1
Volume group "centos" successfully extended
[root@zabbix-server ~]# vgdisplay
--- Volume group ---
VG Name centos
System ID
Format lvm2
Metadata Areas 2
Metadata Sequence No 5
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 2
Open LV 2
Max PV 0
Cur PV 2
Act PV 2
VG Size <119.00 GiB
PE Size 4.00 MiB
Total PE 30463
Alloc PE / Size 30463 / <119.00 GiB
Free PE / Size 0 / 0
VG UUID 280QHe-8dkW-t34f-9JKh-QhMk-1rZE-cejqal
查看逻辑卷，默认系统分了 2 个，选择对应逻辑卷路径
[root@zabbix-server ~]# lvdisplay
--- Logical volume ---
LV Path /dev/centos/root
LV Name root
VG Name centos
LV UUID vhJWup-CgKn-C9xH-dmOv-3iLW-TM4g-ezKp3R
LV Write Access read/write
LV Creation host, time zabbix-server, 2019-07-29 18:48:17 +0800
LV Status available
# open 1
LV Size <111.00 GiB
Current LE 28415
Segments 2
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:0
--- Logical volume ---
LV Path /dev/centos/swap
LV Name swap
VG Name centos
LV UUID 813MLJ-AbCR-hdvv-85hd-L289-GHEH-DDC1Lj
LV Write Access read/write
LV Creation host, time zabbix-server, 2019-07-29 18:48:17 +0800
LV Status available
# open 2
LV Size 8.00 GiB
Current LE 2048
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:1
扩容当前逻辑卷空间
[root@zabbix-server ~]# lvextend /dev/centos/root /dev/sdb1
Size of logical volume centos/root changed from 91.00 GiB (23296 extents) to <111.00 GiB (28415 extents).
Logical volume centos/root successfully resized.
写入文件系统，使扩容生效
[root@zabbix-server ~]# xfs_growfs /dev/mapper/centos-root
meta-data=/dev/mapper/centos-root isize=512 agcount=4, agsize=5963776 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=0 spinodes=0
data = bsize=4096 blocks=23855104, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
log =internal bsize=4096 blocks=11648, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
data blocks changed from 23855104 to 29096960
使用 ext 文件系统，可以使用 resize2fs 命令替换 xfs_growfs 命令。
查看扩容后的物理卷
[root@zabbix-server ~]# pvs
PV VG Fmt Attr PSize PFree
/dev/sda2 centos lvm2 a-- 99.00g 0
/dev/sdb1 centos lvm2 a-- <20.00g 0
查看根分区扩容效果
[root@zabbix-server ~]# df -hT
Filesystem Type Size Used Avail Use% Mounted on
/dev/mapper/centos-root xfs 111G 1.6G 110G 2% /
devtmpfs devtmpfs 1.9G 0 1.9G 0% /dev
tmpfs tmpfs 1.9G 0 1.9G 0% /dev/shm
tmpfs tmpfs 1.9G 12M 1.9G 1% /run
tmpfs tmpfs 1.9G 0 1.9G 0% /sys/fs/cgroup
/dev/sda1 xfs 497M 139M 359M 28% /boot
tmpfs tmpfs 378M 0 378M 0% /run/user/0
新建逻辑分区扩容
查看硬盘信息
查看系统可用块设备以及依赖关系
将新增磁盘格式化为物理卷 PV
[root@zabbix-server ~]# pvcreate /dev/sdb /dev/sdc
Physical volume "/dev/sdb" successfully created.
Physical volume "/dev/sdc" successfully created.
查看 pv 信息
创建卷组（diskvg），并将 PV 加入到卷组中 通过 vgcreate 命令
[root@zabbix-server ~]# vgcreate diskvg /dev/sdb /dev/sdc
Volume group "diskvg" successfully created
通过 vgdisplay 或 vgs 命令查看 vg 的信息
[root@zabbix-server ~]# vgs
VG #PV #LV #SN Attr VSize VFree
centos 1 2 0 wz--n- 99.00g 0
diskvg 2 0 0 wz--n- 19.99g 19.99g
[root@zabbix-server ~]# vgdisplay
--- Volume group ---
VG Name diskvg
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 19.99 GiB
PE Size 4.00 MiB
Total PE 5118
Alloc PE / Size 0 / 0
Free PE / Size 5118 / 19.99 GiB
VG UUID itBEsX-bKdl-lqdf-qd8y-07AG-W12i-lFIvL0
--- Volume group ---
VG Name centos
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 3
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 2
Open LV 2
Max PV 0
Cur PV 1
Act PV 1
VG Size 99.00 GiB
PE Size 4.00 MiB
Total PE 25344
Alloc PE / Size 25344 / 99.00 GiB
Free PE / Size 0 / 0
VG UUID 280QHe-8dkW-t34f-9JKh-QhMk-1rZE-cejqal
基于卷组（VG）创建逻辑卷(LV) 通过 lvcreate 命令
lvcreate -n app1 -L 5G diskvg （基于 diskvg 创建逻辑卷 lv,名字为 app,大小为 5G)
[root@zabbix-server ~]# lvcreate -n app1 -L 5G diskvg
Logical volume "app1" created.
用 lvdisplay 或 lvs 命令查看创建好的逻辑卷。可以看到名字为 app1 的逻辑卷 lv 已经创建好了，它是基于 diskvg 创建的，大小为 5G
[root@zabbix-server ~]# lvs
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
root centos -wi-ao---- 91.00g
swap centos -wi-ao---- 8.00g
app1 diskvg -wi-a----- 5.00g
格式化逻辑卷
[root@zabbix-server ~]# mkfs -t xfs /dev/diskvg/app1
meta-data=/dev/diskvg/app1 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
挂载文件系统
[root@zabbix-server ~]# mkdir /app1
[root@zabbix-server ~]# mount /dev/diskvg/app1 /app1
[root@zabbix-server ~]# df -hT
Filesystem Type Size Used Avail Use% Mounted on
/dev/mapper/centos-root xfs 91G 1.2G 90G 2% /
devtmpfs devtmpfs 1.9G 0 1.9G 0% /dev
tmpfs tmpfs 1.9G 0 1.9G 0% /dev/shm
tmpfs tmpfs 1.9G 12M 1.9G 1% /run
tmpfs tmpfs 1.9G 0 1.9G 0% /sys/fs/cgroup
/dev/sda1 xfs 497M 139M 359M 28% /boot
tmpfs tmpfs 378M 0 378M 0% /run/user/0
添加开机启动
echo "/dev/diskvg/app1 /app1 xfs defaults 0 0" >>/etc/fstab
扩容逻辑卷
查看 vg 信息
[root@zabbix-server app1]# vgs
VG #PV #LV #SN Attr VSize VFree
centos 1 2 0 wz--n- 99.00g 0
diskvg 2 1 0 wz--n- 19.99g 14.99g
卸载文件系统与挂载点关联
umount /app1
扩展逻辑卷至 10G
[root@zabbix-server /]# lvextend -L 10G /dev/diskvg/app1
Size of logical volume diskvg/app1 changed from 5.00 GiB (1280 extents) to 10.00 GiB (2560 extents).
Logical volume diskvg/app1 successfully resized.
挂载文件系统
mount /dev/diskvg/app1 /app1 或 mount -a
重置 LV 容量
[root@zabbix-server /]# xfs_growfs /dev/diskvg/app1
meta-data=/dev/mapper/diskvg-app1 isize=512 agcount=4, agsize=327680 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=0 spinodes=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 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 1310720 to 2621440
查看扩容硬盘信息
