Linux LVM的创建及扩展
Linux LVM的创建及扩展
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，使用lvm用户可以在无需停机的情况下方便地调整各个分区大小。
LVM使用分层结构，如下图所示
基本术语
物理卷（Physical Volume，PV）
指磁盘分区或从逻辑上与磁盘分区具有同样功能的设备（如RAID），是LVM的基本存储逻辑块，但和基本的物理存储介质（如分区、磁盘等）比较，却包含有与LVM相关的管理参数。
*卷组（Volume Group，VG）
类似于非LVM系统中的物理磁盘，其由一个或多个物理卷PV组成。可以在卷组上创建一个或多个LV（逻辑卷）。
*逻辑卷（Logical Volume，LV）
类似于非LVM系统中的磁盘分区，逻辑卷建立在卷组VG之上。在逻辑卷LV之上可以建立文件系统（比如/home或者/usr等）。
（注释：基本术语此段摘抄于百度百科）
简单来说就是：
PV:是物理的磁盘分区
VG:LVM中的物理的磁盘分区，也就是PV，必须加入VG，可以将VG理解为一个仓库或者是几个大的硬盘。
LV：也就是从VG中划分的逻辑分区
如下图所示PV、VG、LV三者关系：
本文将介绍怎么在linux中创建和管理LVM卷。
[[email protected] ~]#fdisk -l
Disk /dev/sda: 21.5 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280bytes
Sector size (logical/physical): 512 bytes /512 bytes
I/O size (minimum/optimal): 512 bytes / 512bytes
Disk identifier: 0x000eeb02
Device Boot Start End Blocks Id System
/dev/sda1 * 1 64 512000 83 Linux
Partition 1 does not end on cylinderboundary.
/dev/sda2 64 1339 10240000 83 Linux
/dev/sda3 1339 1594 2048000 82 Linux swap / Solaris
首先添三块硬盘，每块大小为2G，
添加完成后，我们来查看一下：
[[email protected] ~]#fdisk -l
Disk /dev/sda: 21.5 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280bytes
Sector size (logical/physical): 512 bytes /512 bytes
I/O size (minimum/optimal): 512 bytes / 512bytes
Disk identifier: 0x000eeb02
Device Boot Start End Blocks Id System
/dev/sda1 * 1 64 512000 83 Linux
Partition 1 does not end on cylinderboundary.
/dev/sda2 64 1339 10240000 83 Linux
/dev/sda3 1339 1594 2048000 82 Linux swap / Solaris
Disk /dev/sdd: 2147MB, 2147483648 bytes
255 heads, 63 sectors/track, 261 cylinders
Units = cylinders of 16065 * 512 = 8225280bytes
Sector size (logical/physical): 512 bytes /512 bytes
I/O size (minimum/optimal): 512 bytes / 512bytes
Disk identifier: 0x00000000
Disk /dev/sdc: 2147MB, 2147483648 bytes
255 heads, 63 sectors/track, 261 cylinders
Units = cylinders of 16065 * 512 = 8225280bytes
Sector size (logical/physical): 512 bytes /512 bytes
I/O size (minimum/optimal): 512 bytes / 512bytes
Disk identifier: 0x00000000
Disk /dev/sdb: 2147MB, 2147483648 bytes
255 heads, 63 sectors/track, 261 cylinders
Units = cylinders of 16065 * 512 = 8225280bytes
Sector size (logical/physical): 512 bytes /512 bytes
I/O size (minimum/optimal): 512 bytes / 512bytes
Disk identifier: 0x00000000
从上边的显示结果可以看出，我们已经添加成功了。
创建物理卷PV
[[email protected]~]# pvcreate /dev/sdb
Physical volume "/dev/sdb"successfully created
[[email protected]~]# pvcreate /dev/sdc
Physical volume "/dev/sdc"successfully created
[[email protected]~]# pvcreate /dev/sdd
Physical volume "/dev/sdd"successfully created
使用pvdisplay命令检查物理卷的创建情况
[[email protected]~]# pvdisplay
"/dev/sdb" is a new physical volumeof "2.00 GiB"
--- NEW Physical volume ---
PV Name /dev/sdb
VG Name
PV Size 2.00 GiB
Allocatable NO
PE Size 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID MAvlCx-FFkq-KnGw-THgz-YZ27-wB31-LD2frW
"/dev/sdc" is a new physical volumeof "2.00 GiB"
--- NEW Physical volume ---
PV Name /dev/sdc
VG Name
PV Size 2.00 GiB
Allocatable NO
PE Size 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID MX1ioY-HSYM-LAmC-fZea-Zccc-qEXG-nkQMUf
"/dev/sdd" is a new physical volumeof "2.00 GiB"
--- NEW Physical volume ---
PV Name /dev/sdd
VG Name
PV Size 2.00 GiB
Allocatable NO
PE Size 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID TQ7aAp-WwIz-sD51-3UoY-lkqM-8v1L-nWYScF
创建卷组VG
接下来我们开始创建卷组VG，名为'volume-group1'，使用/dev/sdb, /dev/sdc 和 /dev/sdd3创建。
[[email protected]~]# vgcreate Volume-group1 /dev/sdb /dev/sdc /dev/sdd
Volume group "Volume-group1"successfully created
使用命令vgdisplay验证卷组
[[email protected]~]# vgdisplay
--- Volume group ---
VGName Volume-group1
System ID
Format lvm2
Metadata Areas 3
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 3
Act PV 3
VG Size 5.99 GiB
PE Size 4.00 MiB
Total PE 1533
Alloc PE / Size 0 / 0
Free PE / Size 1533 / 5.99 GiB
VG UUID 9sCwZQ-uFpc-EcSA-c1Jw-BZ75-RRtg-EWaDam
从输出中，我们可以看见卷组的使用量/总量。物理卷给卷组提供空间。只要在这个卷组中还有可用空间，我们就可以随意创建逻辑卷。
创建逻辑卷LV
创建一个名为' lv1'、大小为100MB的逻辑卷
[[email protected] ~]# lvcreate -L 500M -n lv1 Volume-group1
Logicalvolume "lv1" created
[[email protected] ~]# lvdisplay
---Logical volume ---
LVPath /dev/Volume-group1/lv1
LVName lv1
VGName Volume-group1
LVUUID 2VZ8nz-oSkQ-dBYS-6Okj-OxsR-ctZo-6Yvr8n
LV WriteAccess read/write
LVCreation host, time localhost.localdomain, 2016-01-21 21:59:10 +0800
LV Status available
#open 0
LVSize 500.00 MiB
CurrentLE 125
Segments 1
Allocation inherit
Readahead sectors auto
-currently set to 256
Blockdevice 253:0
现在逻辑卷已经准备好了，我们可以格式化和挂载逻辑卷，就像其它ext2/3/4分区一样.
[[email protected] ~]# mkfs.ext4 /dev/Volume-group1/lv1
mke2fs 1.41.12 (17-May-2010)
文件系统标签=
操作系统:Linux
块大小=1024 (log=0)
分块大小=1024 (log=0)
Stride=0 blocks, Stripe width=0 blocks
128016 inodes, 512000 blocks
25600 blocks (5.00%) reserved for the super user
第一个数据块=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
正在写入inode表: 完成
Creating journal (8192 blocks): 完成
Writing superblocks and filesystem accountinginformation: 完成
This filesystem will be automatically checkedevery 29 mounts or
180 days, whichever comes first. Use tune2fs -c or -i to override.
[[email protected] ~]# mkdir /lvm-mount
[[email protected] ~]# mount /dev/Volume-group1/lv1 /lvm-mount/
一旦逻辑卷挂载，我们就可以到挂载点 /lvm-mount/ 上读写了。
[[email protected] ~]# cd /lvm-mount/
[[email protected] lvm-mount]# ll
总用量 12
drwx------. 2 root root 12288 1月 21 22:05lost+found
[[email protected] lvm-mount]# touch cheshi.txt
[[email protected] lvm-mount]# mkdir ceshi
[[email protected] lvm-mount]# ll
总用量 15
drwxr-xr-x. 2 root root 1024 1月 21 22:08 ceshi
-rw-r--r--. 1 root root 0 1月 21 22:08 cheshi.txt
drwx------. 2 root root 12288 1月 21 22:05lost+found
扩展一个lvm卷
调整逻辑卷大小的功能是LVM最有用的功能。这个部分会讨论我们怎么样扩展一个存在的逻辑卷。下面，我们将会扩展先前创建的逻辑卷‘lv1’扩大到800MB。
[[email protected] ~]# lvextend -L +300M /dev/Volume-group1/lv1
Extending logical volume lv1 to 800.00 MiB
Logical volume lv1 successfully resized
[[email protected] ~]# lvdisplay
--- Logical volume ---
LV Path /dev/Volume-group1/lv1
LV Name lv1
VG Name Volume-group1
LV UUID 2VZ8nz-oSkQ-dBYS-6Okj-OxsR-ctZo-6Yvr8n
LV Write Access read/write
LV Creation host, time localhost.localdomain,2016-01-21 21:59:10 +0800
LV Status available
# open 1
LV Size 800.00 MiB
Current LE 200
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 253:0
转载于:https://blog.51cto.com/aihua/1737478