LVM扩展学习日志

lvm是逻辑卷管理的简称,它将一个或多个物理硬盘分区(PV)组成一个逻辑硬盘(VG)来使用,  然后从这个VG中划分出逻辑分区(LV), 以上概念是我理解的东西,可能和书上的不一样。

以下所有命令都是在CENTOS6.5上进行操作的

1:对磁盘进行分区

使用fdisk对磁盘进行分区。注意分区的格式,LVM对应的是8e, 创建完成后记得重启电脑。

Command (m for help): p

Disk /dev/vda: 85.9 GB, 85899345920 bytes
16 heads, 63 sectors/track, 166440 cylinders
Units = cylinders of 1008 * 512 = 516096 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00035557

   Device Boot      Start         End      Blocks   Id  System
/dev/vda1   *           3        1018      512000   83  Linux
Partition 1 does not end on cylinder boundary.
/dev/vda2            1018       41611    20458496   8e  Linux LVM
Partition 2 does not end on cylinder boundary.
/dev/vda3           41611      166440    62914240   8e  Linux LVM

2: 创建PV

pvcreate使用磁盘分区来创建PV

[root@centos-vm-73 ~]# pvcreate  /dev/vda3
  Physical volume "/dev/vda3" successfully created
[root@centos-vm-73 ~]# pvdisplay 
  --- Physical volume ---
  PV Name               /dev/vda2
  VG Name               vg_centos6
  PV Size               19.51 GiB / not usable 3.00 MiB
  Allocatable           yes (but full)
  PE Size               4.00 MiB
  Total PE              4994
  Free PE               0
  Allocated PE          4994
  PV UUID               YzeBUf-Pxvv-5fct-I5Mz-6NDg-fIsI-Zjv7RT
   
  "/dev/vda3" is a new physical volume of "60.00 GiB"
  --- NEW Physical volume ---
  PV Name               /dev/vda3
  VG Name               
  PV Size               60.00 GiB
  Allocatable           NO
  PE Size               0   
  Total PE              0
  Free PE               0
  Allocated PE          0
  PV UUID               5B99Bs-waNc-QSnO-YWu5-XdMH-xRB6-epWFzJ

3:创建VG

如果已经有VG的话那么不需要创建新的VG,直接把PV添加到VG中就可以了。

[root@centos-vm-73 ~]# vgdisplay 
  --- Volume group ---
  VG Name               vg_centos6
  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               19.51 GiB
  PE Size               4.00 MiB
  Total PE              4994
  Alloc PE / Size       4994 / 19.51 GiB
  Free  PE / Size       0 / 0   
  VG UUID               wyjVpO-L0jl-ckoF-SU4K-JTNd-p3Nb-YwMgO9
   
[root@centos-vm-73 ~]# vgcreate  vg_centos6_1 /dev/vda3

创建vg的使用后面可以跟多个PV(pv和磁盘分区同名)。

如果想把PV添加到已经存在的vg中使用下面的命令:

[root@centos-vm-73 ~]# vgextend vg_centos6 /dev/vda3
  Volume group "vg_centos6" successfully extended

3:创建LV

显示当前的lv

[root@centos-vm-73 ~]# lvdisplay 
  --- Logical volume ---
  LV Path                /dev/vg_centos6/lv_root
  LV Name                lv_root
  VG Name                vg_centos6
  LV UUID                4QMRdu-2JYb-a7BM-OSw9-nRrz-nGmV-Z80yeO
  LV Write Access        read/write
  LV Creation host, time centos6.5, 2014-06-11 12:13:40 +0800
  LV Status              available
  # open                 1
  LV Size                17.54 GiB
  Current LE             4490
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:0
   
  --- Logical volume ---
  LV Path                /dev/vg_centos6/lv_swap
  LV Name                lv_swap
  VG Name                vg_centos6
  LV UUID                8awkxq-UpsI-mPml-GTrx-tWDu-MkhI-tA3OhS
  LV Write Access        read/write
  LV Creation host, time centos6.5, 2014-06-11 12:13:43 +0800
  LV Status              available
  # open                 1
  LV Size                1.97 GiB
  Current LE             504
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:1

创建一个新的LV

 lvcreate -L  10G -n data  vg_centos6

-L指定分区的大小,-n指定分区名,vg_centos6是vg名字

扩展LV,有时不想添加新的分区,那么可以扩展该LV 

   
[root@centos-vm-73 ~]# lvextend -L +18G   /dev/vg_centos6/lv_root
  Extending logical volume lv_root to 77.00 GiB
  Logical volume lv_root successfully resized
[root@centos-vm-73 ~]# resize2fs  /dev/vg_centos6/lv_root
resize2fs 1.41.12 (17-May-2010)
Filesystem at /dev/vg_centos6/lv_root is mounted on /; on-line resizing required
old desc_blocks = 4, new_desc_blocks = 5
Performing an on-line resize of /dev/vg_centos6/lv_root to 20185088 (4k) blocks.
The filesystem on /dev/vg_centos6/lv_root is now 20185088 blocks long.

[root@centos-vm-73 ~]# df -h
Filesystem                      Size  Used Avail Use% Mounted on
/dev/mapper/vg_centos6-lv_root   76G  4.9G   71G   7% /
tmpfs                           940M   72K  940M   1% /dev/shm
/dev/vda1                       485M   40M  421M   9% /boot

注意-L的参数是 +18G,在扩展LV的容量后需要resize2fs是容量生效

4: 格式化文件系统

如果生成了新的LV,那么需要对分区进行文件系统格式化

mkfs.ext4   /dev/vg_centos6/lv_root

然后mout,最后修改/etc/fstab.

原文地址:https://www.cnblogs.com/gaoxing/p/4374477.html