Lvm
是逻辑卷管理（
logical Volume manager
）的简称是在
linux
下的一种管理机制
,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，
lvm
是磁盘分区和文件系统之间添加的一个逻辑层，来为下层磁盘分区布局，提供一个抽象的盘卷，在盘卷上建立文件系统
第一部分
先创建三个但分区，且每个分区为
1G
并把该分区改为
LVM
的文件类型，
lvm
的代号是
8e
1
首先创建物理卷
# pvcreate /dev/sdb1
Physical volume "/dev/sdb1" successfully created
2
查看创建的物理卷
#pvdisplay /dev/sdb1
/dev/cdrom: open failed: No medium found
--- Physical volume ---
PV Name /dev/sda2
VG Name vol0
PV Size 17.58 GB / not usable 18.53 MB
Allocatable yes
PE Size (KByte) 32768
Total PE 562
Free PE 291
Allocated PE 271
PV UUID 08q5Bg-Q1No-xGPj-Nl8y-IrAx-tuOU-Q8RsGi
"/dev/sdb1" is a new physical volume of "964.81 MB"
--- NEW Physical volume ---
PV Name /dev/sdb1
VG Name
PV Size 964.81 MB
Allocatable NO
PE Size (KByte) 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID G15TOa-rLX3-DqqC-oE44-TKXR-1jqE-A0guz6
3
创建逻辑卷组
# vgcreate vol1 /dev/sdb1
Volume group "vol1" successfully created
4
查看创建的逻辑卷组
# vgdispaly /dev/vol1
--- Volume group ---
VG Name vol1
System ID
Format lvm2
Metadata Areas 1
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 1
Act PV 1
VG Size 964.00 MB
PE Size 4.00 MB
Total PE 241
Alloc PE / Size 0 / 0
Free PE / Size 241 / 964.00 MB
VG UUID TpscPr-FA4g-t3fv-WXty-o6u0-KtXf-Cv0Ge6
4
创建逻辑卷
#lvcreate -L 500M -n lv1 /dev/vol1
Insufficient free extents (241) in volume group vol1: 256 required
Logical volume "lv1" created
5
查看创建的逻辑卷
#lvdiisplay /dev/vol1/lv1
--- Logical volume ---
LV Name /dev/vol1/lv1
VG Name vol1
LV UUID YsaXYW-Hkcx-Kl1B-Cdrq-C7Tw-8hhQ-Bhhvy9
LV Write Access read/write
LV Status available
# open 0
LV Size 500.00 MB
Current LE 125
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 253:2
5
创建目录
#mkdir /lv1
6
格式化逻辑卷
# mkfs.ext3 /dev/vol1/lv1
mke2fs 1.39 (29-May-2006)
Filesystem label=
OS type: Linux
Block size=1024 (log=0)
Fragment size=1024 (log=0)
128016 inodes, 512000 blocks
25600 blocks (5.00%) reserved for the super user
First data block=1
Maximum filesystem blocks=67633152
63 block groups
8192 blocks per group, 8192 fragments per group
2032 inodes per group
Superblock backups stored on blocks:
8193, 24577, 40961, 57345, 73729, 204801, 221185, 401409
Writing inode tables: done
Creating journal (8192 blocks): done
Writing superblocks and filesystem accounting information: done
This filesystem will be automatically checked every 36 mounts or
180 days, whichever comes first. Use tune2fs -c or -i to override.
7
挂载逻辑卷
#mount /dev/vol1/lv1 /lv1
如果想要开机启动自动挂载需要编辑文件
/etc/fstab
/dev/vol1/lv1 /lv1 ext3 defaults 0 0
8
扩展逻辑组
# vgextend vol1 /dev/sdb7
Volume group "vol1" successfully extended
9
查看逻辑组
#vgs --name /dev/vol1
VG #PV #LV #SN Attr VSize VFree
LVM2_VG_NAME='vol1' LVM2_PV_COUNT='2' LVM2_LV_COUNT='1' LVM2_SNAP_COUNT='0' LVM2_VG_ATTR='wz--n-' LVM2_VG_SIZE='1.88G' LVM2_VG_FREE='1.39G'
10
扫描逻辑组的
# vgscan
Reading all physical volumes. This may take a while...
Found volume group "vol1" using metadata type lvm2
Found volume group "vol0" using metadata type lvm2
11
能够显示所有的逻辑组包括隐藏的逻辑组
# vgexport -a
Volume group "vol1" has active logical volumes
Volume group "vol0" has active logical volumes
12
能够隐藏所有的逻辑组
# vgimport -a
Volume group "vol1" is not exported
Volume group "vol0" is not exported
13
扩展逻辑卷的大小
#lvextend -L +200M /dev/vol1/lv1
Extending logical volume lv1 to 700.00 MB
Logical volume lv1 successfully resized
注：
lvextend -L [+|-] numM
设备名
“
+
”
表示在原大小的上再增加
numM
“
-
”
表示在原大小上减小
numM
什么不加时表示扩展到的大小
第二部分
缩减逻辑卷的大小
1
先卸载逻辑卷
#umount /dev/vol1/lv1
2
检测磁盘
#fsck -f
fsck 1.39 (29-May-2006)
e2fsck 1.39 (29-May-2006)
/dev/vol0/root is mounted.
WARNING!!! Running e2fsck on a mounted filesystem may cause
SEVERE filesystem damage.
Do you really want to continue (y/n)? yes
/dev/vol0/root: recovering journal
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/vol0/root: ***** FILE SYSTEM WAS MODIFIED *****
/dev/vol0/root: ***** REBOOT LINUX *****
/dev/vol0/root: 109901/2097152 files (0.7% non-contiguous), 758106/2097152 blocks
3
强制检测逻辑卷
# e2fsck -f /dev/vol1/lv1
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/vol1/lv1: 12/128016 files (8.3% non-contiguous), 26703/512000 blocks
4
指定缩减的大小
# resize2fs /dev/vol1/lv1 400M
resize2fs 1.39 (29-May-2006)
Resizing the filesystem on /dev/vol1/lv1 to 409600 (1k) blocks.
The filesystem on /dev/vol1/lv1 is now 409600 blocks long.
5
执行缩减的命令
# lvreduce -L 400M /dev/vol1/lv1
WARNING: Reducing active logical volume to 400.00 MB
THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce lv1? [y/n]: y
Reducing logical volume lv1 to 400.00 MB
Logical volume lv1 successfully resized
6
查看缩减后的逻辑卷
# lvdisplay /dev/vol1/lv1
--- Logical volume ---
LV Name /dev/vol1/lv1
VG Name vol1
LV UUID u0apc1-UDbE-4mOB-RnlM-5xC2-hGLX-9ciDTQ
LV Write Access read/write
LV Status available
# open 0
LV Size 400.00 MB
Current LE 100
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 253:2
7
重新挂载
#mount /dev/vol1/lv1 /lv1
第三部分
制作逻辑卷的快照
# lvcreate -L 50M -s -p r -n lv1snap /dev/vol1/lv1
Rounding up size to full physical extent 52.00 MB
Logical volume "lv1snap" created
2
创建目录
#mkdir /lv1snap
3
挂载快照
# mount /dev/vol1/lv1snap /lv1snap
mount: block device /dev/vol1/lv1snap is write-protected, mounting read-only
本文转自 freehat08 51CTO博客，原文链接：http://blog.51cto.com/freehat/278892，如需转载请自行联系原作者
