linux使用lvm分区

lvm分区

试验环境 centos 6.5

借图如下

linux使用lvm分区

 

 

一、LVM原理
传统文件系统,比如这个盘只有300G,那么建立在这个300G上面的文件系统最多只能用到300G,但是有了LVM这个功能后,我们建立文件系统的盘就不是建立在物理盘上,而是建立在一个叫LV逻辑卷上面,这个卷是一个逻辑概念不是物理盘,空间可能大于一个物理盘,也可能小于一个物理盘。而且这个LV逻辑卷的空间可以扩展和缩小,这样就给上层的文件系统提供了更好的支持。
需要理解的几个概念:
PV(Physical Volume):物理空间的意思,其实就是指一个分区(如/dev/sdb1 )或者是一个盘(如/dev/sdb)
VG(Volume Group):相当于一个Pool,由多个PV组成的pool
LV(Logical Volume):用来建立一个文件系统的空间,这个空间来源于VG,大小随意,可以扩展。(比如/dev/mapper/rhel-root这个目录其实是一个文件系统挂载点,这个点就是承载在一个LV上,这个文件系统的大小就是这个LV的大小。 )

 

 二、实际操作

1、使用fdisk -l查看磁盘情况,可以看到我有两块未分区的磁盘,分别是/dev/sdb /dev/sdc,我们先用一块磁盘/dev/sdb进行测试。

[root@test_iptables ~]# fdisk -l

Disk /dev/sdb: 1073 MB, 1073741824 bytes
255 heads, 63 sectors/track, 130 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000


Disk /dev/sda: 21.5 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x0005b552

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1          39      307200   83  Linux
Partition 1 does not end on cylinder boundary.
/dev/sda2              39        2350    18566144   83  Linux
/dev/sda3            2350        2611     2097152   82  Linux swap / Solaris

Disk /dev/sdc: 1073 MB, 1073741824 bytes
255 heads, 63 sectors/track, 130 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

2、对/dev/sdb进行分区

(1)先进行标准分区

[root@test_iptables ~]# fdisk /dev/sdb
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel with disk identifier 0x34c351e7.
Changes will remain in memory only, until you decide to write them.
After that, of course, the previous content wont be recoverable.

Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)

WARNING: DOS-compatible mode is deprecated. Its strongly recommended to
         switch off the mode (command c) and change display units to
         sectors (command u).

Command (m for help): n
Command action
   e   extended
   p   primary partition (1-4)
p
Partition number (1-4): 1
First cylinder (1-130, default 1): 
Using default value 1
Last cylinder, +cylinders or +size{K,M,G} (1-130, default 130): 
Using default value 130

Command (m for help): w
The partition table has been altered!

Calling ioctl() to re-read partition table.
Syncing disks.

(2)查看使用vgdisplay查看已经存在的卷组名称

[root@test_iptables ~]# vgdisplay
  No volume groups found

(3)开始进行lvm处理

创建物理卷(PV)

[root@test_iptables ~]# pvcreate /dev/sdb1 
  dev_is_mpath: failed to get device for 8:17
  Physical volume "/dev/sdb1" successfully created

创建卷组(VG)

[root@test_iptables ~]# vgcreate vg01 /dev/sdb1
  Volume group "vg01" successfully created

查看创建的物理卷及卷组

linux使用lvm分区

 

 

 在卷组vg01上创建名为date,大小为1000M的逻辑卷

[root@test_iptables ~]# lvcreate -L 1000M -n data vg01
  Logical volume "data" created

linux使用lvm分区

 

 

 3、格式化分区

[root@test_iptables ~]# mkfs.ext4 /dev/vg01/data
mke2fs 1.41.12 (17-May-2010)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
64000 inodes, 256000 blocks
12800 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=264241152
8 block groups
32768 blocks per group, 32768 fragments per group
8000 inodes per group
Superblock backups stored on blocks: 
    32768, 98304, 163840, 229376

Writing inode tables: done                            
Creating journal (4096 blocks): done
Writing superblocks and filesystem accounting information: done

This filesystem will be automatically checked every 33 mounts or
180 days, whichever comes first.  Use tune2fs -c or -i to override.

4、挂载分区

[root@test_iptables ~]# mkdir /u01
[root@test_iptables ~]# mount /dev/vg01/data /u01/
[root@test_iptables ~]# df -h
Filesystem             Size  Used Avail Use% Mounted on
/dev/sda2               18G  9.2G  7.4G  56% /
tmpfs                  931M   72K  931M   1% /dev/shm
/dev/sda1              291M   39M  238M  14% /boot
/dev/mapper/vg01-data  985M   18M  918M   2% /u01

5、设置开机自动挂载

[root@test_iptables ~]# cat /etc/fstab 

#
# /etc/fstab
# Created by anaconda on Wed Sep 11 09:19:25 2019
#
# Accessible filesystems, by reference, are maintained under /dev/disk
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
UUID=fe5d2642-dc89-45a2-963a-2a5e0f7e5a3a /                       ext4    defaults        1 1
UUID=e356222c-cde8-4f30-a38c-3fcf905b65c8 /boot                   ext4    defaults        1 2
UUID=4d5bbee9-6557-4b6b-a275-4c43b14dce9d swap                    swap    defaults        0 0
tmpfs                   /dev/shm                tmpfs   defaults        0 0
devpts                  /dev/pts                devpts  gid=5,mode=620  0 0
sysfs                   /sys                    sysfs   defaults        0 0
proc                    /proc                   proc    defaults        0 0
/dev/vg01/data          /u01                    ext4    defaults        0 0

至此,一个lvm分区设置完毕

linux使用lvm分区

 

 

三、PV扩容

1、首先进行标准分区

root@test_iptables ~]# fdisk /dev/sdc
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel with disk identifier 0x114bf00d.
Changes will remain in memory only, until you decide to write them.
After that, of course, the previous content wont be recoverable.

Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)

WARNING: DOS-compatible mode is deprecated. Its strongly recommended to
         switch off the mode (command c) and change display units to
         sectors (command u).

Command (m for help): n
Command action
   e   extended
   p   primary partition (1-4)
p
Partition number (1-4): 1
First cylinder (1-130, default 1): 
Using default value 1
Last cylinder, +cylinders or +size{K,M,G} (1-130, default 130): 
Using default value 130

Command (m for help): w
The partition table has been altered!

Calling ioctl() to re-read partition table.
Syncing disks.

2、创建物理卷

[root@test_iptables ~]# pvcreate /dev/sdc1
  Physical volume "/dev/sdc1" successfully created

3、VG扩容

将新的物理卷加入卷组

[root@test_iptables ~]# vgextend vg01 /dev/sdc1
  Volume group "vg01" successfully extended

扩展逻辑卷 并resize2fs加载逻辑卷

[root@test_iptables ~]# lvextend -l +100%FREE /dev/vg01/data
  Extending logical volume data to 1.98 GiB
  Logical volume data successfully resized
[root@test_iptables ~]# resize2fs /dev/vg01/data
resize2fs 1.41.12 (17-May-2010)
Filesystem at /dev/vg01/data is mounted on /u01; on-line resizing required
old desc_blocks = 1, new_desc_blocks = 1
Performing an on-line resize of /dev/vg01/data to 520192 (4k) blocks.
The filesystem on /dev/vg01/data is now 520192 blocks long.

至此,以上就是整个流程,成功扩展为2G。

 

linux使用lvm分区

 

linux使用lvm分区

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