逻辑卷的结构图
物理硬盘：存储文件设备（/dev/sdb）
PV（物理卷）：硬盘的分区或者卷
VG（卷组）：由一个或者多个物理卷组成的LVM卷。
LV（逻辑卷）：VG上的分区，可以在LV上创建文件系统。
PE:PE上的最小存储单元，默认为4MB。
1.下面我们以实际的创建过程做演示：
创建两个主分区，一个为4G，一个为6G
[root@192 ~]# fdisk /dev/sdb
Command (m for help): n
Command action
e extended
p primary partition (1-4)
p#指定主分区
Partition number (1-4): 1#指定分区号码
First cylinder (1-7832, default 1):
Using default value 1#指定分区起始柱面
Last cylinder, +cylinders or +size{K,M,G} (1-7832, default 7832): +4G#指定分区大小
Command (m for help): n
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4): 2
First cylinder (524-7832, default 524):
Using default value 524
Last cylinder, +cylinders or +size{K,M,G} (524-7832, default 7832): +6G
Command (m for help): p
Disk /dev/sdb: 64.4 GB, 64424509440 bytes
255 heads, 63 sectors/track, 7832 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xb089f8a1
Device Boot Start End Blocks Id System#查看已创建的分区
/dev/sdb1 1 523 4200966 83 Linux
/dev/sdb2 524 1307 6297480 83 Linux
Command (m for help): L#查看逻辑卷需指定的设备类型
0 Empty 24 NEC DOS 81 Minix / old Lin bf Solaris
1 FAT12 39 Plan 9 82 Linux swap / So c1 DRDOS/sec (FAT-
2 XENIX root 3c PartitionMagic 83 Linux c4 DRDOS/sec (FAT-
3 XENIX usr 40 Venix 80286 84 OS/2 hidden C: c6 DRDOS/sec (FAT-
4 FAT16 <32M 41 PPC PReP Boot 85 Linux extended c7 Syrinx
5 Extended 42 SFS 86 NTFS volume set da Non-FS data
6 FAT16 4d QNX4.x 87 NTFS volume set db CP/M / CTOS / .
7 HPFS/NTFS 4e QNX4.x 2nd part 88 Linux plaintext de Dell Utility
8 AIX 4f QNX4.x 3rd part 8e Linux LVM df BootIt
9 AIX bootable 50 OnTrack DM 93 Amoeba e1 DOS access
a OS/2 Boot Manag 51 OnTrack DM6 Aux 94 Amoeba BBT e3 DOS R/O
b W95 FAT32 52 CP/M 9f BSD/OS e4 SpeedStor
c W95 FAT32 (LBA) 53 OnTrack DM6 Aux a0 IBM Thinkpad hi eb BeOS fs
e W95 FAT16 (LBA) 54 OnTrackDM6 a5 FreeBSD ee GPT
f W95 Ext'd (LBA) 55 EZ-Drive a6 OpenBSD ef EFI (FAT-12/16/
10 OPUS 56 Golden Bow a7 NeXTSTEP f0 Linux/PA-RISC b
11 Hidden FAT12 5c Priam Edisk a8 Darwin UFS f1 SpeedStor
12 Compaq diagnost 61 SpeedStor a9 NetBSD f4 SpeedStor
14 Hidden FAT16 <3 63 GNU HURD or Sys ab Darwin boot f2 DOS secondary
16 Hidden FAT16 64 Novell Netware af HFS / HFS+ fb VMware VMFS
17 Hidden HPFS/NTF 65 Novell Netware b7 BSDI fs fc VMware VMKCORE
18 AST SmartSleep 70 DiskSecure Mult b8 BSDI swap fd Linux raid auto
1b Hidden W95 FAT3 75 PC/IX bb Boot Wizard hid fe LANstep
1c Hidden W95 FAT3 80 Old Minix be Solaris boot ff BBT
1e Hidden W95 FAT1
Command (m for help): t
Partition number (1-4): 1
Hex code (type L to list codes): 8e#调整逻辑卷的设备类型
Changed system type of partition 1 to 8e (Linux LVM)
Command (m for help): t
Partition number (1-4): 2
Hex code (type L to list codes): 8e#调整逻辑卷的设备类型
Changed system type of partition 2 to 8e (Linux LVM)
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
2.查看内核识别的分区
[root@192 ~]# cat /proc/partitions
major minor #blocks name
8 0 20971520 sda
8 1 512000 sda1
8 2 15360000 sda2
8 3 1024000 sda3
8 4 1 sda4
8 5 4073472 sda5
8 16 62914560 sdb
8 17 4200966 sdb1#刚分的两个区
8 18 6297480 sdb2#刚分的两个区
3.[root@192 ~]# pvcreate /dev/sdb{1,2} #创建pv
Physical volume "/dev/sdb1" successfully created
Physical volume "/dev/sdb2" successfully created
4.kpartx -af /dev/sdb
5.[root@192 ~]# pvs#显示创建的pv
PV VG Fmt Attr PSize PFree
/dev/mapper/sdb1 lvm2 --- 4.01g 4.01g
/dev/mapper/sdb2 lvm2 --- 6.01g 6.01g
6.[root@192 ~]# pvdisplay#查看逻辑卷详细信息
"/dev/mapper/sdb1" is a new physical volume of "4.01 GiB"
--- NEW Physical volume ---
PV Name /dev/mapper/sdb1
VG Name
PV Size 4.01 GiB
Allocatable NO
PE Size 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID 4d2BDI-gJzg-1ZKa-0zcV-7eSg-Bytv-D3LT7y
"/dev/mapper/sdb2" is a new physical volume of "6.01 GiB"
--- NEW Physical volume ---
PV Name /dev/mapper/sdb2
VG Name
PV Size 6.01 GiB
Allocatable NO
PE Size 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID oDcOG6-I7sd-IVHk-gNqi-8CdF-QurW-SPd8x1
7.vgcreate myvg /dev/sdb{1,2}#创建vg并把组名命名为myvg
Volume group "myvg" successfully created
8.[root@192 ~]# vgs#查看已创建的卷组
VG #PV #LV #SN Attr VSize VFree
myvg 2 0 0 wz--n- 10.01g 10.01g
9.[root@192 ~]# fdisk /dev/sdc#新加一块磁盘sdc
Command (m for help): n
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4): 1
First cylinder (1-1305, default 1):
Using default value 1
Last cylinder, +cylinders or +size{K,M,G} (1-1305, default 1305):
Using default value 1305
Command (m for help): t
Selected partition 1
Hex code (type L to list codes): 8e
Changed system type of partition 1 to 8e (Linux LVM)
Command (m for help): p
Disk /dev/sdc: 10.7 GB, 10737418240 bytes
255 heads, 63 sectors/track, 1305 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x66ea7a6a
Device Boot Start End Blocks Id System
/dev/sdc1 1 1305 10482381 8e Linux LVM
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
10.[root@192 ~]# cat /proc/partitions#查看内核是否识别
major minor #blocks name
8 0 20971520 sda
8 1 512000 sda1
8 2 15360000 sda2
8 3 1024000 sda3
8 4 1 sda4
8 5 4073472 sda5
8 16 62914560 sdb
8 17 4200966 sdb1
8 18 6297480 sdb2
8 19 4200997 sdb3
8 32 10485760 sdc
8 33 10482381 sdc1
11.[root@192 ~]# pvcreate /dev/sdc1#先创建物理卷pv
Physical volume "/dev/sdc1" successfully created
[root@192 ~]# pvs#查看已有的pv
PV VG Fmt Attr PSize PFree
/dev/sdb1 myvg lvm2 a-- 4.00g 4.00g
/dev/sdb2 myvg lvm2 a-- 6.00g 6.00g
/dev/sdc1 myvg lvm2 a-- 9.99g 9.99g
[root@192 ~]# pvdisplay#查看已有的pv的详细信息
--- Physical volume ---
PV Name /dev/sdb1
VG Name myvg
PV Size 4.01 GiB / not usable 6.51 MiB
Allocatable yes
PE Size 8.00 MiB#逻辑卷最基本的块
Total PE 512
Free PE 512
Allocated PE 0
PV UUID 4d2BDI-gJzg-1ZKa-0zcV-7eSg-Bytv-D3LT7y
--- Physical volume ---
PV Name /dev/sdb2
VG Name myvg
PV Size 6.01 GiB / not usable 5.88 MiB
Allocatable yes
PE Size 8.00 MiB
Total PE 768
Free PE 768
Allocated PE 0
PV UUID oDcOG6-I7sd-IVHk-gNqi-8CdF-QurW-SPd8x1
--- Physical volume ---#下面显示的是新加的pv
PV Name /dev/sdc1
VG Name myvg
PV Size 10.00 GiB / not usable 4.70 MiB
Allocatable yes
PE Size 8.00 MiB
Total PE 1279
Free PE 1279
Allocated PE 0
PV UUID 6iS5Sn-lvUu-F3pC-3WGZ-ao6l-kWuy-Tfwt0X
12.[root@192 ~]# vgextend myvg /dev/sdc1#把新加的pv(/dev/sdc1)加入卷组myvg
Volume group "myvg" successfully extended
[root@192 ~]# vgs#查看vg信息
VG #PV #LV #SN Attr VSize VFree
myvg 3 0 0 wz--n- 19.99g 19.99g
[root@192 ~]# vgdisplay#查看vg详细信息
--- Volume group ---
VG Name myvg
System ID
Format lvm2
Metadata Areas 3
Metadata Sequence No 2
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 19.99 GiB
PE Size 8.00 MiB
Total PE 2559
Alloc PE / Size 0 / 0
Free PE / Size 2559 / 19.99 GiB
VG UUID 3cZU0o-LILk-BdGf-e0gm-JjDE-TI33-1VWFlh
13.[root@192 ~]# lvcreate -L 3G -n lv1 myvg#从卷组myvg中创建一个逻辑卷命名为lv1，大小为3G Logical volume "lv1" created
[root@192 ~]# lvs#查看已创建的逻辑卷
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
lv1 myvg -wi-a----- 3.00g
[root@192 ~]# lvdisplay#查看已创建的逻辑卷的详细信息
--- Logical volume ---
LV Path /dev/myvg/lv1
LV Name lv1
VG Name myvg
LV UUID hEC4C3-twue-FQ7K-7y1t-oeG2-N0xx-2eFXLS
LV Write Access read/write
LV Creation host, time 192.168.10.123, 2016-05-06 14:30:35 +0800
LV Status available
# open 0
LV Size 3.00 GiB
Current LE 384
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 253:0
14.[root@192 ~]# mke2fs -t ext4 -b 2048 /dev/myvg/lv1#对新创建的逻辑卷lv1进行格式化，把该逻辑卷格式化为ext4的类型，指定块大小为2048
mke2fs 1.41.12 (17-May-2010)
文件系统标签=
操作系统:Linux
块大小=2048 (log=1)
分块大小=2048 (log=1)
Stride=0 blocks, Stripe width=0 blocks
196608 inodes, 1572864 blocks
78643 blocks (5.00%) reserved for the super user
第一个数据块=0
Maximum filesystem blocks=538968064
96 block groups
16384 blocks per group, 16384 fragments per group
2048 inodes per group
Superblock backups stored on blocks:
16384, 49152, 81920, 114688, 147456, 409600, 442368, 802816, 1327104
正在写入inode表: 完成
Creating journal (32768 blocks): 完成
Writing superblocks and filesystem accounting information: 完成
This filesystem will be automatically checked every 31 mounts or
180 days, whichever comes first. Use tune2fs -c or -i to override.
15.[root@192 /]# mount /dev/myvg/lv1 /u01#挂载逻辑卷/dev/myvg/lv1 到 /u01下面
[root@192 /]# df -h#查看已挂载的分区，看到逻辑卷已挂载到/u01下面
Filesystem Size Used Avail Use% Mounted on
/dev/sda2 15G 4.0G 9.7G 29% /
tmpfs 499M 72K 499M 1% /dev/shm
/dev/sda1 477M 28M 424M 7% /boot
/dev/sda5 3.8G 7.8M 3.6G 1% /opt
/dev/mapper/myvg-lv1 2.9G 11M 2.8G 1% /u01
16.假如逻辑卷空间不够用，那我们需要扩展逻辑卷
先查看卷组的剩余可用空间
[root@192 /]# vgs
VG #PV #LV #SN Attr VSize VFree
myvg 3 1 0 wz--n- 19.99g 14.99g
17.[root@192 /]# lvextend -L 5G /dev/myvg/lv1 #直接把逻辑卷扩展到5G
Size of logical volume myvg/lv1 changed from 3.00 GiB (384 extents) to 5.00 GiB (640 extents).
Logical volume lv1 successfully resized
18.[root@192 /]# lvs#查看扩展后的逻辑卷的大小
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
lv1 myvg -wi-ao---- 5.00g
19.[root@192 /]# df -h#查看分区信息，发现我们只扩展了逻辑卷的物理边界，逻辑卷的逻辑边界并没有动，还是为原来创建的3G
Filesystem Size Used Avail Use% Mounted on
/dev/sda2 15G 4.0G 9.7G 29% /
tmpfs 499M 72K 499M 1% /dev/shm
/dev/sda1 477M 28M 424M 7% /boot
/dev/sda5 3.8G 7.8M 3.6G 1% /opt
/dev/mapper/myvg-lv1 2.9G 11M 2.8G 1% /u01
20.[root@192 /]# resize2fs /dev/myvg/lv1#使用resize2fs扩充逻辑卷的逻辑边界，使用在线扩充resize2fs 1.41.12 (17-May-2010)
Filesystem at /dev/myvg/lv1 is mounted on /u01; on-line resizing required
old desc_blocks = 2, new_desc_blocks = 3
Performing an on-line resize of /dev/myvg/lv1 to 2621440 (2k) blocks.
The filesystem on /dev/myvg/lv1 is now 2621440 blocks long.
21.[root@192 /]# df -h#再查看分区信息，可以看到逻辑卷/dev/myvg/lv1已扩充到5G
Filesystem Size Used Avail Use% Mounted on
/dev/sda2 15G 4.0G 9.7G 29% /
tmpfs 499M 72K 499M 1% /dev/shm
/dev/sda1 477M 28M 424M 7% /boot
/dev/sda5 3.8G 7.8M 3.6G 1% /opt
/dev/mapper/myvg-lv1 4.9G 11M 4.6G 1% /u01
逻辑卷扩展步骤：
1.先确定扩展的大小：并确保所属的卷组有足够的剩余空间
2.扩展物理边界：
Lvextend -L [+]Size /path/to/lv_device
3.扩展逻辑边界：
resize2fs /path/to/lv_device
缩减逻辑卷步骤：
1.卸载卷，并执行强制检测
e2fsck -f /path/to/lv_device
2.缩减逻辑边界：
resize2fs /path/to/lv_device SIZE
3.缩减物理边界：
lvreduce -L [-]Size /path/to/lv_device
LVM一些常用的命令
物理卷管理命令：pv
pvcreate,pvremove,pvscan,pvs,pvdisplay,pvmove
卷组管理命令：vg
vgcreate，vgs，vgdisplay，vgextend,vgremove,vgrename
vgcreate
-s: PE大小，默认4M
逻辑卷的管理命令：lv
lvcreate，lvdisplay，lvs，lvextend，lvreduce，lvremove
lvcreate
- L ： 空间大小
- n : lv 名称
