lvm快速使用

1. fdisk -l 查看可用分区

[root@localhost ~]# fdisk -l

Disk /dev/cciss/c0d0: 146.7 GB, 146778685440 bytes
255 heads, 63 sectors/track, 17844 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

           Device Boot      Start         End      Blocks   Id  System
/dev/cciss/c0d0p1   *           1          16      128488+  83  Linux
/dev/cciss/c0d0p2              17         799     6289447+  83  Linux
/dev/cciss/c0d0p4            1322       17844   132720997+   5  Extended
/dev/cciss/c0d0p6            2105        2626     4192933+  82  Linux swap

Disk /dev/cciss/c0d1: 293.5 GB, 293564211200 bytes
255 heads, 32 sectors/track, 70265 cylinders
Units = cylinders of 8160 * 512 = 4177920 bytes

Disk /dev/cciss/c0d1 doesn't contain a valid partition table

2. 选取启用一个设备，来启用lvm
2.1 创建一个物理设备

[root@localhost ~]# pvcreate /dev/cciss/c0d1
  Physical volume "/dev/cciss/c0d1" successfully created

看看啥结果：

[root@localhost ~]# pvdisplay -v
    Scanning for physical volume names
  --- Physical volume ---
  PV Name               /dev/cciss/c0d1
  VG Name               data
  PV Size               273.40 GB / not usable 664.00 KB
  Allocatable           yes
  PE Size (KByte)       4096
  Total PE              69991
  Free PE               46698
  Allocated PE          23293
  PV UUID               ElM1rp-UYEw-KlV8-JjGu-cO17-5BIo-plyXXq

 
2.2 创建一个卷组

[root@localhost ~]# vgcreate data /dev/cciss/c0d1
  Volume group "data" successfully created

看看结果：

[root@localhost ~]# vgdisplay -v
    Finding all volume groups
    Finding volume group "data"
  --- Volume group ---
  VG Name               data
  System ID
  Format                lvm2
  Metadata Areas        1
  Metadata Sequence No  3
  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               272.24 GB
  PE Size               4.00 MB
  Total PE              69694
  Alloc PE / Size       0 / 0
  Free  PE / Size       69694 / 272.24 GB
  VG UUID               7UcyGl-TYPr-3c82-2oew-eJ3F-6Z1b-mVtM7G

  --- Physical volumes ---
  PV Name               /dev/cciss/c0d1
  PV UUID               7Y4Vze-WR95-uDDJ-exi8-IPVD-gEEW-Tqpuy2
  PV Status             allocatable
  Total PE / Free PE    69694 / 69694

2.3 创建一个lvm卷

[root@localhost ~]# lvcreate -L 60G -n mysql data
  Logical volume "mysql" created

看看：

[root@localhost ~]#lvdisplay -v
    Finding all logical volumes
  --- Logical volume ---
  LV Name                /dev/data/mysql
  VG Name                data
  LV UUID                bO5R6V-UVhX-yaJw-Ap0a-fQIe-AfYy-OJ0XyT
  LV Write Access        read/write
  LV Status              available
  # open                 1
  LV Size                90.99 GB
  Current LE             23293
  Segments               1
  Allocation             inherit
  Read ahead sectors     0
  Block device           253:0

 
估计不够大，来给它加大一点，呵呵

[root@localhost ~]# lvresize -L +10G /dev/data/mysql
  Extending logical volume mysql to 70.00 GB
  Logical volume mysql successfully resized

2.4 创建文件系统

[root@localhost ~]# mkfs.ext3 -j /dev/data/mysql
......
......

然后挂载到你想要的地方。

在这里要注意了，想要使得加大的空间生效，必须再一次执行 ext2online 。

[root@localhost ~]# ext2online /dev/data/mysql
ext2online v1.1.18 - 2001/03/18 for EXT2FS 0.5b

3. 简单测试一下
挂载

[root@localhost ~]# mount /dev/data/mysql /mysql
[root@localhost ~]# ls -l /mysql/
total 0

往目标目录下拷贝一个文件：

[root@localhost ~]# cp test.tgz /mysql
[root@localhost ~]# ls -l /mysql
total 1176
-rw-r--r--  1 root root 1196796 May  5 16:20 test.tgz

ok，现在创建一下快照：

[root@localhost ~]# lvcreate -L 10M -s -n snap /dev/data/mysql
  Rounding up size to full physical extent 12.00 MB
  Logical volume "snap" created

然后把快照挂载，看看都有啥咚咚：

[root@localhost ~]# mount /dev/data/snap /snap
[root@localhost ~]# ls -l /snap
total 1176
-rw-r--r--  1 root root 1196796 May  5 16:20 linux.tgz

 
呵呵，看到了吧，快照生效。这个时候，如果想要备份，只需要把里面的文件拷贝出来即可，然后尽快删除快照。