Linux LVM逻辑卷管理工具的使用方法
[info]1、基础概念[/info]
LVM是 Logical Volume Manager（逻辑卷管理）的简写，它是Linux环境下对磁盘分区进行管理的一种机制，它由Heinz Mauelshagen在Linux 2.4内核上实现。
Linux用户安装Linux操作系统时遇到的一个常见的难以决定的问题就是如何正确地评估各分区大小，以分配合适的硬盘空间。普通的磁盘分区管理方式在逻辑分区划分好之后就无法改变其大小，当一个逻辑分区存放不下某个文件时，这个文件因为受上层文件系统的限制，也不能跨越多个分区来存放，所以也不能同时放到别的磁盘上。而遇到出现某个分区空间耗尽时，解决的方法通常是使用符号链接，或者使用调整分区大小的工具，但这只是暂时解决办法，没有从根本上解决问题。随着Linux的逻辑卷管理功能的出现，这些问题都迎刃而解，用户在无需停机的情况下可以方便地调整各个分区大小。
PV (Physical Volumn 物理卷)
VG(Volumn Group 物理卷组)
LV(Logical Volumn 逻辑卷)
PE(Physical Extend 物理块 default 4M);
LE(Logical Extend 逻辑块)
PE:LE=1:1(Normal)
LVM各个组件的关系示意图
[info]1.5、预先需要将添加的硬盘进行分区[/info]
fdisk -l fdisk /dev/sdb
[info]2、虚拟机上增加一块硬盘，并创建几个分区sdb1和sdb2[/info]
这里就不详细讲述创建分区的方法了。
Disk /dev/sdb: 32.2 GB, 32212254720 bytes 255 heads, 63 sectors/track, 3916 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Device Boot Start End Blocks Id System /dev/sdb1 1 1000 8032468+ 83 Linux /dev/sdb2 1001 2000 8032500 83 Linux
[info]3、创建物理卷（PV）pvcreate,pvs[/info]
[root@oracle ~]# pvcreate /dev/sdb{1,2}
Physical volume "/dev/sdb1" successfully created
Physical volume "/dev/sdb2" successfully created
[root@oracle ~]# pvs
/dev/hdc: open failed: No medium found
PV VG Fmt Attr PSize PFree
/dev/sda2 VolGroup00 lvm2 a- 99.88G 0
/dev/sdb1 lvm2 -- 7.66G 7.66G
/dev/sdb2 lvm2 -- 7.66G 7.66G
[info]4、创建卷组(VG) vgcreate,vgdisplay[/info]
[root@oracle ~]# vgdisplay
--- Volume group ---
VG Name VolGroup00
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 99.88 GB
PE Size 32.00 MB
Total PE 3196
Alloc PE / Size 3196 / 99.88 GB
Free PE / Size 0 / 0
VG UUID f8N3vv-ejHh-wU1x-zv96-jyiR-yFf5-2G7BwK
[root@oracle ~]# vgcreate -v VolGroup01 /dev/sdb{1,2}
Wiping cache of LVM-capable devices
Adding physical volume '/dev/sdb1' to volume group 'VolGroup01'
Adding physical volume '/dev/sdb2' to volume group 'VolGroup01'
Archiving volume group "VolGroup01" metadata (seqno 0).
Creating volume group backup "/etc/lvm/backup/VolGroup01" (seqno 1).
Volume group "VolGroup01" successfully created
[root@oracle ~]# vgdisplay
--- Volume group ---
VG Name VolGroup01
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 15.32 GB
PE Size 4.00 MB
Total PE 3922
Alloc PE / Size 0 / 0
Free PE / Size 3922 / 15.32 GB
VG UUID pGE9tH-k5oz-Qt20-I8JZ-tuFb-qMca-OsVLTV
[info]5、删除（VG） vgremove[/info]
[root@oracle ~]# vgremove VolGroup01
Volume group "VolGroup01" successfully removed
通过 -s 调整VG的PE大小
[root@oracle ~]# vgcreate -v -s 32M VolGroup01 /dev/sdb{1,2}
Wiping cache of LVM-capable devices
Adding physical volume '/dev/sdb1' to volume group 'VolGroup01'
Adding physical volume '/dev/sdb2' to volume group 'VolGroup01'
Archiving volume group "VolGroup01" metadata (seqno 0).
Creating volume group backup "/etc/lvm/backup/VolGroup01" (seqno 1).
Volume group "VolGroup01" successfully created
[root@oracle ~]# vgdisplay
--- Volume group ---
VG Name VolGroup01
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 15.31 GB
PE Size 32.00 MB
Total PE 490
Alloc PE / Size 0 / 0
Free PE / Size 490 / 15.31 GB
VG UUID pFJKA1-METh-vMph-9PbB-1fNC-sxV0-e9axc7
[info]6、创建逻辑卷(LVM) lvcreate[/info]
lvcreate [options] -n 逻辑卷名 卷组名
其中的常用可选项有：
"-i Stripes ：采用交错(striped)方式创建LV，其中Stripes指卷组中PV的数量。
"-I Stripe_size ：采用交错方式时采用的块大小(单位为KB)，Stripe_size必须为2的指数：2N ，N=2,3...9。
"-l LEs ：指定LV的逻辑块数。
"-L size ：指定LV的大小，其后可以用K、M、G表示KB、MB、GB。
"-s ：创建一已存在LV的snapshot卷。
"-n name ：为LV指定名称。
创建普通LV：
lvcreate -L 5G -n lv01 vg01 创建一个名为lv01的5G 虚拟分区在虚拟硬盘vg01上 /dev/vg01/lv01
lvcreate -i 4 -I 8 -L 4G -n lv02 vg01 [-i 是VG中组成PV的分区个数，-I 块大小，-L LV的大小]
创建快照LV：
lvcreate -s -i 4 -I 16 -L 2G -n lv03_snapshot vg01
[root@oracle ~]# lvcreate -L 5G -n lv01 VolGroup01
Logical volume "lv01" created
[root@oracle ~]# lvdisplay
--- Logical volume ---
LV Name /dev/VolGroup01/lv01
VG Name VolGroup01
LV UUID B2nmqM-NFjv-zFso-JG2l-X2rc-OVzO-9bF9WJ
LV Write Access read/write
LV Status available
# open 0
LV Size 5.00 GB
Current LE 160
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 253:2
[info]7、创建文件系统[/info]
[root@oracle ~]# mke2fs -j /dev/VolGroup01/lv01
mke2fs 1.39 (29-May-2006)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
655360 inodes, 1310720 blocks
65536 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=1342177280
40 block groups
32768 blocks per group, 32768 fragments per group
16384 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done
This filesystem will be automatically checked every 32 mounts or
180 days, whichever comes first. Use tune2fs -c or -i to override.
[info]8、挂载[/info]
[root@oracle /]# mkdir /u02
[root@oracle /]# mount /dev/VolGroup01/lv01 /u02
[root@oracle /]# df
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/mapper/VolGroup00-LogVol00
97445468 29006156 63409424 32% /
/dev/sda1 101086 12070 83797 13% /boot
tmpfs 3276800 0 3276800 0% /dev/shm
/dev/mapper/VolGroup01-lv01
5160576 141440 4756992 3% /u02
[info]9、增、减LV大小： lvextend[/info]
[root@oracle /]# umount /u02 [root@oracle /]# lvs LV VG Attr LSize Origin Snap% Move Log Copy% Convert LogVol00 VolGroup00 -wi-ao 95.94G LogVol01 VolGroup00 -wi-ao 3.94G lv01 VolGroup01 -wi-a- 5.00G [root@oracle /]# vgdisplay --- Volume group --- VG Name VolGroup01 System ID Format lvm2 Metadata Areas 2 Metadata Sequence No 2 VG Access read/write VG Status resizable MAX LV 0 Cur LV 1 Open LV 0 Max PV 0 Cur PV 2 Act PV 2 VG Size 15.31 GB PE Size 32.00 MB Total PE 490 Alloc PE / Size 160 / 5.00 GB Free PE / Size 330 / 10.31 GB VG UUID pFJKA1-METh-vMph-9PbB-1fNC-sxV0-e9axc7 [root@oracle /]# lvextend -L +100M /dev/VolGroup01/lv01 Rounding up size to full physical extent 128.00 MB Extending logical volume lv01 to 5.12 GB Logical volume lv01 successfully resized [root@oracle /]# lvs LV VG Attr LSize Origin Snap% Move Log Copy% Convert LogVol00 VolGroup00 -wi-ao 95.94G LogVol01 VolGroup00 -wi-ao 3.94G lv01 VolGroup01 -wi-a- 5.12G [root@oracle /]# vgdisplay --- Volume group --- VG Name VolGroup01 System ID Format lvm2 Metadata Areas 2 Metadata Sequence No 3 VG Access read/write VG Status resizable MAX LV 0 Cur LV 1 Open LV 0 Max PV 0 Cur PV 2 Act PV 2 VG Size 15.31 GB PE Size 32.00 MB Total PE 490 Alloc PE / Size 164 / 5.12 GB Free PE / Size 326 / 10.19 GB VG UUID pFJKA1-METh-vMph-9PbB-1fNC-sxV0-e9axc7
[info]10、扩充VG[/info]
[root@oracle /]# fdisk /dev/sdb The number of cylinders for this disk is set to 3916. There is nothing wrong with that, but this is larger than 1024, and could in certain setups cause problems with: 1) software that runs at boot time (e.g., old versions of LILO) 2) booting and partitioning software from other OSs (e.g., DOS FDISK, OS/2 FDISK) Command (m for help): p Disk /dev/sdb: 32.2 GB, 32212254720 bytes 255 heads, 63 sectors/track, 3916 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Device Boot Start End Blocks Id System /dev/sdb1 1 1000 8032468+ 83 Linux /dev/sdb2 1001 2000 8032500 83 Linux Command (m for help): n Command action e extended p primary partition (1-4) p Partition number (1-4): 3 First cylinder (2001-3916, default 2001): Using default value 2001 Last cylinder or +size or +sizeM or +sizeK (2001-3916, default 3916): 3000 Command (m for help): p Disk /dev/sdb: 32.2 GB, 32212254720 bytes 255 heads, 63 sectors/track, 3916 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Device Boot Start End Blocks Id System /dev/sdb1 1 1000 8032468+ 83 Linux /dev/sdb2 1001 2000 8032500 83 Linux /dev/sdb3 2001 3000 8032500 83 Linux Command (m for help): w The partition table has been altered! Calling ioctl() to re-read partition table. WARNING: Re-reading the partition table failed with error 16: Device or resource busy. The kernel still uses the old table. The new table will be used at the next reboot. Syncing disks. 使用新分区创建物理卷 [root@oracle ~]# pvcreate /dev/sdb3 Physical volume "/dev/sdb3" successfully created 将新分区加入到物理卷组中 [root@oracle ~]# vgextend VolGroup01 /dev/sdb3 Volume group "VolGroup01" successfully extended 查看物理卷组信息 [root@oracle ~]# pvs PV VG Fmt Attr PSize PFree /dev/sda2 VolGroup00 lvm2 a- 99.88G 0 /dev/sdb1 VolGroup01 lvm2 a- 7.66G 2.53G /dev/sdb2 VolGroup01 lvm2 a- 7.66G 7.66G /dev/sdb3 VolGroup01 lvm2 a- 14.66G 14.66G
[info]11、扩充LV逻辑卷空间[/info]
查看逻辑卷组信息
[root@oracle ~]# lvs
LV VG Attr LSize Origin Snap% Move Log Copy% Convert
LogVol00 VolGroup00 -wi-ao 95.94G
LogVol01 VolGroup00 -wi-ao 3.94G
lv01 VolGroup01 -wi-a- 5.12G
扩展逻辑卷lv01 500M空间
[root@oracle ~]# lvextend -L +500M /dev/VolGroup01/lv01
Rounding up size to full physical extent 512.00 MB
Extending logical volume lv01 to 5.62 GB
Logical volume lv01 successfully resized
[root@oracle ~]# pvs
PV VG Fmt Attr PSize PFree
/dev/sda2 VolGroup00 lvm2 a- 99.88G 0
/dev/sdb1 VolGroup01 lvm2 a- 7.66G 2.03G
/dev/sdb2 VolGroup01 lvm2 a- 7.66G 7.66G
/dev/sdb3 VolGroup01 lvm2 a- 14.66G 14.66G
[root@oracle ~]# lvs
LV VG Attr LSize Origin Snap% Move Log Copy% Convert
LogVol00 VolGroup00 -wi-ao 95.94G
LogVol01 VolGroup00 -wi-ao 3.94G
lv01 VolGroup01 -wi-a- 5.62G
挂载文件系统，查看a.txt仍在，说明扩展文件系统空间时，文件不会丢失
[root@oracle ~]# mount /dev/VolGroup01/lv01 /u02
[root@oracle ~]# df
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/mapper/VolGroup00-LogVol00
97445468 29005128 63410452 32% /
/dev/sda1 101086 12070 83797 13% /boot
tmpfs 3276800 0 3276800 0% /dev/shm
/dev/mapper/VolGroup01-lv01
5160576 141448 4756984 3% /u02
[root@oracle ~]# cd /u02
[root@oracle u02]# ll
total 24
-rw-r--r-- 1 root root 21 Jun 26 08:41 a.txt
drwx------ 2 root root 16384 Jun 26 08:39 lost+found
[info]12、缩小LV逻辑卷空间[/info]
[root@oracle /]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/VolGroup00-LogVol00
93G 28G 61G 32% /
/dev/sda1 99M 12M 82M 13% /boot
tmpfs 3.2G 0 3.2G 0% /dev/shm
/dev/mapper/VolGroup01-lv01
5.0G 139M 4.6G 3% /u02
[root@oracle /]# umount /u02
检查文件系统
[root@oracle /]# e2fsck -f -y /dev/VolGroup01/lv01
e2fsck 1.39 (29-May-2006)
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/VolGroup01/lv01: 12/655360 files (8.3% non-contiguous), 55938/1310720 blocks
重新定义文件系统大小，空间调整到300M
[root@oracle /]# resize2fs /dev/VolGroup01/lv01 300M
resize2fs 1.39 (29-May-2006)
Resizing the filesystem on /dev/VolGroup01/lv01 to 76800 (4k) blocks.
The filesystem on /dev/VolGroup01/lv01 is now 76800 blocks long.
resize2fs /dev/mapper/VolGroup-lv_root 6105088
再次检查文件系统
[root@oracle /]# e2fsck -f /dev/VolGroup01/lv01
e2fsck 1.39 (29-May-2006)
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/VolGroup01/lv01: 12/49152 files (8.3% non-contiguous), 34994/76800 blocks
重新定义lv大小，调整到300M，这个要大于文件系统重新定义的空间
[root@oracle /]# lvreduce -L 300 /dev/VolGroup01/lv01
Rounding up size to full physical extent 320.00 MB
WARNING: Reducing active logical volume to 320.00 MB
THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce lv01? [y/n]: y
Reducing logical volume lv01 to 320.00 MB
Logical volume lv01 successfully resized
查看逻辑卷信息，已经调整到300M
[root@oracle /]# lvs
LV VG Attr LSize Origin Snap% Move Log Copy% Convert
LogVol00 VolGroup00 -wi-ao 95.94G
LogVol01 VolGroup00 -wi-ao 3.94G
lv01 VolGroup01 -wi-a- 320.00M
[root@oracle /]#
重新挂载文件系统，a.txt没有丢失，成功缩小了文件系统。
[root@oracle /]# mount /dev/VolGroup01/lv01 /u01
[root@oracle /]# cd u01
[root@oracle u01]# ls
a.txt