LVM逻辑卷管理

LVM是逻辑盘卷管理（Logical Volume Manager）的简称，LVM将多个物理分区/磁盘从逻辑上组合成一个更大的整体，从其中划分出不同的逻辑分区，逻辑分区的大小可以根据需求扩大和缩减。相比普通的磁盘存储LVM具有灵活的容量、可伸缩的存储空间的优点。1,公司想把四块20G的磁盘利用起来，单独使用容量太小，所以要做成LVM逻辑卷。（实际运用中企业硬盘容量不止20G，此处只是拿来举例参考）
[root@localhost ~]# fdisk -l

Disk /dev/sda: 85.8 GB, 85899345920 bytes
255 heads, 63 sectors/track, 10443 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

DeviceBoot Start End Blocks Id System
/dev/sda1 * 1 13 104391 83 Linux
/dev/sda2 14 2624 20972857+ 83 Linux
/dev/sda3 2625 2885 2096482+ 82 Linux swap / Solaris
/dev/sda4 2886 10443 60709635 5 Extended
/dev/sda5 2886 4102 9775521 83 Linux
/dev/sda6 4103 5319 9775521 7 HPFS/NTFS

Disk/dev/sdb: 21.4 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk /dev/sdb doesn't contain a valid partition table

Disk/dev/sdc: 21.4 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk /dev/sdc doesn't contain a valid partition table

Disk/dev/sdd: 21.4 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk /dev/sdd doesn't contain a valid partition table

Disk/dev/sde: 21.4 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk /dev/sde doesn't contain a valid partition table
2，创建物理卷
[root@localhost~]# pvcreate /dev/{sdb,sdc,sdd,sde}
Writing physical volume data to disk"/dev/sdb"
Physical volume "/dev/sdb" successfullycreated
Writing physical volume data to disk"/dev/sdc"
Physical volume "/dev/sdc"successfully created
Writing physical volume data to disk"/dev/sdd"
Physical volume "/dev/sdd"successfully created
Writing physical volume data to disk"/dev/sde"
Physical volume "/dev/sde"successfully created
3，查看是否创建成功
[root@localhost~]# pvscan
PV /dev/sdb lvm2 [20.00 GB]
PV /dev/sdc lvm2 [20.00 GB]
PV /dev/sdd lvm2 [20.00 GB]
PV /dev/sde lvm2 [20.00 GB]
Total: 4 [80.00 GB] / in use: 0 [0 ] / in no VG: 4 [80.00 GB]……容量为80G
4，创建卷组并指定PE大小为8M，并查看是否创建成功
[root@localhost~]# vgcreate-s 8M vg_data /dev/{sdb,sdc,sdd,sde}
Volume group "vg_data" successfullycreated
[root@localhost~]# vgdisplay
--- Volume group ---
VG Name vg_data
System ID
Format lvm2
Metadata Areas 4
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 4
Act PV 4
VG Size 79.97 GB……大小约为80G
PE Size 8.00 M……PE大小为8M
Total PE 10236
Alloc PE / Size 0 / 0
Free PE / Size 10236 / 79.97 GB
VG UUID nr2ozz-SdLK-GaJc-kwIQ-elbT-HPD1-nWOVCH
5，激活卷组
[root@localhost~]# vgchange –ay……-ay表示active yes，即激活；如果-an则表示关闭激活
0 logical volume(s) in volume group"vg_data" now active
6，创建逻辑卷大小为50G，并验证是否创建成功
[root@localhost~]# lvcreate -L 50G -n lv_data vg_data
Logical volume "lv_data" created
[root@localhost~]# lvdisplay
--- Logical volume ---
LV Name /dev/vg_data/lv_data
VG Name vg_data
LV UUID nYhCyl-MOB1-lcBc-NVJx-Zv6n-Yf2P-svS4U2
LV Write Access read/write
LV Status available
# open 0
LV Size 50.00 GB……创建成功，大小50G
Current LE 6400
Segments 3
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 253:0
7，格式化逻辑卷
[root@localhost~]# mkfs.ext3 /dev/vg_data/lv_data
mke2fs 1.39(29-May-2006)
Filesystemlabel=
OS type: Linux
Block size=4096(log=2)
Fragmentsize=4096 (log=2)
6553600 inodes,13107200 blocks
655360 blocks(5.00%) reserved for the super user
First datablock=0
Maximumfilesystem blocks=4294967296
400 block groups
32768 blocks pergroup, 32768 fragments per group
16384 inodes pergroup
Superblockbackups stored on blocks:
32768, 98304, 163840, 229376, 294912,819200, 884736, 1605632, 2654208,
4096000, 7962624, 11239424

Writing inodetables: done
Creating journal(32768 blocks): done
Writingsuperblocks and filesystem accounting information: done

This filesystemwill be automatically checked every 24 mounts or
180 days,whichever comes first. Use tune2fs -c or-i to override.
8，把逻辑卷挂载到/data/LVM
[root@localhost~]# vim /etc/fstab ……设置开机自动挂载

LABEL=/ / ext3 defaults 1 1
LABEL=/boot /boot ext3 defaults 1 2
tmpfs /dev/shm tmpfs defaults 0 0
devpts /dev/pts devpts gid=5,mode=620 0 0
sysfs /sys sysfs defaults 0 0
proc /proc proc defaults 0 0
LABEL=SWAP-sda3 swap swap defaults 0 0
/dev/sda6 /NTFS ntfs-3g defaults 0 0 UUID="171d2c3c-2b2a-4a59-8a04-6a6a047ce531"/data/LVM ext3 defaults 00
~
~
9,75 All
[root@localhost~]# mount–a……加载fstab中的配置
9，查看挂载情况
[root@localhost ~]# df -lT
Filesystem Type 1K-blocks Used Available Use% Mounted on
/dev/sda2 ext3 20315844 2715924 16551280 15% /
/dev/sda1 ext3 101086 12200 83667 13% /boot
tmpfs tmpfs 511920 0 511920 0% /dev/shm
/dev/sda6 fuseblk 9775520 49624 9725896 1% /NTFS
/dev/mapper/vg_data-lv_data
ext3 51606140 184272 48800428 1% /data/LVM……挂载成功
10，现在逻辑卷需要扩展到99G，再添加一块20G磁盘，扩展逻辑卷步骤如下：
[root@localhost ~]#pvcreate /dev/sdf
……

root@localhost ~]#vgextend vg_data /dev/sdf
Volume group "vg_data" successfully extended
[root@localhost ~]#vgdisplay vg_data
---Volume group ---
VGName vg_data
System ID
Format lvm2
Metadata Areas 5
Metadata Sequence No 3
VGAccess read/write
VGStatus resizable
MAXLV 0
CurLV 1
Open LV 1
MaxPV 0
CurPV 5
ActPV 5
VG Size 99.96 GB
PESize 8.00 MB
……

[root@localhost ~]# lvextend -L 99G /dev/vg_data/lv_data
Extending logical volume lv_data to 99.00 GB
Logicalvolume lv_data successfully resized
11,查看容量的扩展情况
[root@localhost ~]# resize2fs/dev/vg_data/lv_data……resize2fs/dev/卷组名/逻辑卷名----更新文件系统,解决df -l查看时lvm扩展后容量没有改变的情况.
resize2fs 1.39 (29-May-2006)
Filesystem at /dev/vg_data/lv_data is mounted on/LVM; on-line resizing required
Performing an on-line resize of /dev/vg_data/lv_datato 25952256 (4k) blocks.
The filesystem on /dev/vg_data/lv_data is now25952256 blocks long.

[root@localhost ~]# df -lT
Filesystem Type 1K-blocks Used Available Use% Mounted on
/dev/sda2 ext3 20315844 2718436 16548768 15% /
/dev/sda1 ext3 101086 12200 83667 13% /boot
tmpfs tmpfs 511920 0 511920 0% /dev/shm
/dev/sda6 fuseblk 9775520 49624 9725896 1% /NTFS
/dev/mapper/vg_data-lv_data
ext3 102180192 192252 96798116 1% /data/LVM
12，扩展：移除LVM的方法(以以上为例)
（1）umount /data/LVM（2）pvremove /dev/vg_data/lv_data（3）vgremove vg_data（4）lvremove /dev/sd[b-f]