簡介
LVM是邏輯盤卷管理（LogicalVolumeManager）的簡稱，它是Linux環境下對磁盤分區進行管理的一種機制，LVM是建立在硬盤和 分區之上的一個邏輯層，來提高磁盤分區管理的靈活性。通過LVM系統管理員可以輕鬆管理磁盤分區，如：將若干個磁盤分區連接爲一個整塊的卷組 （volumegroup），形成一個存儲池。管理員可以在卷組上隨意創建邏輯卷組（logicalvolumes），並進一步在邏輯卷組上創建文件系 統。管理員通過LVM可以方便的調整存儲卷組的大小，並且可以對磁盤存儲按照組的方式進行命名、管理和分配。
環境準備
Linux發行版本：Centos7
開始操作
- 檢查一下磁盤使用情況：
[root@localhost admin]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/centos-root 50G 1.4G 49G 3% / #將給/目錄擴容50G
devtmpfs 16G 0 16G 0% /dev
tmpfs 16G 0 16G 0% /dev/shm
tmpfs 16G 17M 16G 1% /run
tmpfs 16G 0 16G 0% /sys/fs/cgroup
/dev/vda1 1014M 145M 870M 15% /boot
/dev/mapper/centos-home 42G 243M 41G 1% /home #將給/home目錄擴容350G
tmpfs 3.2G 0 3.2G 0% /run/user/1000
[root@localhost admin]# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
fd0 2:0 1 4K 0 disk
sr0 11:0 1 1024M 0 rom
vda 252:0 0 100G 0 disk
├─vda1 252:1 0 1G 0 part /boot
└─vda2 252:2 0 99G 0 part
├─centos-root 253:0 0 50G 0 lvm / #注意此處，將擴容50G
├─centos-swap 253:1 0 7.9G 0 lvm [SWAP]
└─centos-home 253:2 0 41.1G 0 lvm /home #注意此處，將擴容350G
vdb 252:16 0 400G 0 disk
- 創建分區
[root@localhost admin]# fdisk /dev/vdb
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 0x9b37b4a1.
Command (m for help): n # 添加新分區
Partition type:
p primary (0 primary, 0 extended, 4 free)
e extended
Select (default p): # 分區類型，回車，默認p，主分區
Using default response p
Partition number (1-4, default 1): # 分區號，回車，默認1
First sector (2048-838860799, default 2048): # 回車，默認起始位置
Using default value 2048
Last sector, +sectors or +size{K,M,G} (2048-838860799, default 838860799): # 回車，默認最後位置
Using default value 838860799
Partition 1 of type Linux and of size 400 GiB is set
Command (m for help): t # 更改分區格式
Selected partition 1
Hex code (type L to list all codes): L # 查看可選項
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 # 更改分區格式爲LVM
Changed type of partition 'Linux' to 'Linux LVM'
Command (m for help): p # 打印，查看改好的分區（blocks爲分區大小 單位爲kb）
Disk /dev/vdb: 429.5 GB, 429496729600 bytes, 838860800 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: 0x9b37b4a1
Device Boot Start End Blocks Id System
/dev/vdb1 2048 838860799 419429376 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.
- 再次查看分區，只是分區好，沒掛載沒加入系統根，無法使用
[root@localhost admin]# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
fd0 2:0 1 4K 0 disk
sr0 11:0 1 1024M 0 rom
vda 252:0 0 100G 0 disk
├─vda1 252:1 0 1G 0 part /boot
└─vda2 252:2 0 99G 0 part
├─centos-root 253:0 0 50G 0 lvm /
├─centos-swap 253:1 0 7.9G 0 lvm [SWAP]
└─centos-home 253:2 0 41.1G 0 lvm /home
vdb 252:16 0 400G 0 disk
└─vdb1 252:17 0 400G 0 part
- 把新的分區轉換爲物理卷
[root@localhost admin]# pvcreate /dev/vdb1
Physical volume "/dev/vdb1" successfully created.
- 查看現有的卷組名，這裏爲centos
[root@localhost admin]# vgdisplay
--- Volume group ---
VG Name centos # 這是Centos系統下默認的VG Name,RHEL系統顯示爲rhel
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 <99.00 GiB
PE Size 4.00 MiB
Total PE 25343
Alloc PE / Size 25342 / 98.99 GiB
Free PE / Size 1 / 4.00 MiB
VG UUID rZR1wr-c9jd-RALA-wwIU-zkGO-fJtC-w9TGZh
- 把轉換號的物理卷併到vg（卷組）中
[root@localhost admin]# vgextend centos /dev/vdb1
Volume group "centos" successfully extended
[root@localhost admin]# 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 3
Open LV 3
Max PV 0
Cur PV 2
Act PV 2
VG Size 498.99 GiB # 此處空間已擴展
PE Size 4.00 MiB
Total PE 127742
Alloc PE / Size 25342 / 98.99 GiB
Free PE / Size 102400 / 400.00 GiB
VG UUID rZR1wr-c9jd-RALA-wwIU-zkGO-fJtC-w9TGZh
- 查看邏輯卷，系統分了3個，選擇對應邏輯卷路徑
[root@localhost admin]# lvdisplay
--- Logical volume ---
LV Path /dev/centos/swap
LV Name swap
VG Name centos
LV UUID KZkj21-9nMn-7r5C-i4R1-nebQ-E0yz-9QOrge
LV Write Access read/write
LV Creation host, time localhost, 2019-12-11 00:28:35 +0800
LV Status available
# open 2
LV Size <7.88 GiB
Current LE 2016
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:1
--- Logical volume ---
LV Path /dev/centos/home # 後面將擴展該邏輯卷，記住此路徑
LV Name home
VG Name centos
LV UUID 2XyDak-rwgq-QEoi-bPsP-uBlO-Y8Kk-cCdG4H
LV Write Access read/write
LV Creation host, time localhost, 2019-12-11 00:28:36 +0800
LV Status available
# open 1
LV Size <41.12 GiB
Current LE 10526
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:2
--- Logical volume ---
LV Path /dev/centos/root # 後面將擴展該邏輯卷，記住此路徑
LV Name root
VG Name centos
LV UUID e8DRcw-DS3l-Q2zY-Bfi2-zF9I-48ee-e202ng
LV Write Access read/write
LV Creation host, time localhost, 2019-12-11 00:28:38 +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
- 給邏輯卷擴展空間
[root@localhost admin]# lvextend -L +50G /dev/centos/root # 給/dev/centos/root擴容50G
Size of logical volume centos/root changed from 50.00 GiB (12800 extents) to 100.00 GiB (25600 extents).
Logical volume centos/root successfully resized.
[root@localhost admin]# lvextend -L +350G /dev/centos/home # 給/dev/centos/home擴容350G
Size of logical volume centos/home changed from <41.12 GiB (10526 extents) to <391.12 GiB (100126 extents).
Logical volume centos/home successfully resized.
說明：
lvextend命令 用於在線擴展邏輯卷的空間大小，而不中斷應用程序對邏輯卷的訪問。使用lvextend命令動態在線擴展磁盤空間，整個空間擴展過程對於應用程序來說是完全透明的。
語法：
lvextend(選項)(參數)
選項：
-L：指定邏輯卷的大小，單位爲“kKmMgGtT”字節；
-l：指定邏輯卷的大小（LE數）。
參數：
邏輯卷：指定要擴展空間的邏輯卷。
- 寫入文件系統，使擴容生效
[root@localhost admin]# xfs_growfs /dev/centos/root
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 26214400
[root@localhost admin]# xfs_growfs /dev/centos/home
meta-data=/dev/mapper/centos-home isize=512 agcount=4, agsize=2694656 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=0 spinodes=0
data = bsize=4096 blocks=10778624, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
log =internal bsize=4096 blocks=5263, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
data blocks changed from 10778624 to 102529024
如果是ext系統，可以使用resize2fs命令替換xfs_growfs命令。
10. 檢查擴容效果
[root@localhost admin]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/centos-root 100G 1.7G 99G 2% /
devtmpfs 16G 0 16G 0% /dev
tmpfs 16G 0 16G 0% /dev/shm
tmpfs 16G 17M 16G 1% /run
tmpfs 16G 0 16G 0% /sys/fs/cgroup
/dev/vda1 1014M 145M 870M 15% /boot
/dev/mapper/centos-home 392G 245M 391G 1% /home
tmpfs 3.2G 0 3.2G 0% /run/user/1000
tmpfs 3.2G 0 3.2G 0% /run/user/0