Linux LVM学习总结——创建卷组VG

在Linux平台如何创建一个卷组(VG)呢?下面简单介绍一下卷组(VG)的创建步骤。本文实验平台为Red Hat Enterprise Linux Server release 6.6 (Santiago)

1： 查看当前卷组信息

查看服务器的卷组(VG)、物理卷(PV)、逻辑卷(LV)相关信息，在此之前，我们先来看看一些基本命令以及用法

vgcan命令介绍 :

查找系统中存在的LVM卷组，并显示找到的卷组列表。vgscan命令仅显示找到的卷组的名称和LVM元数据类型，要得到卷组的详细信息需要使用vgdisplay命令。

vgscan的参数：

[—cache]Scan devices for LVM physical volumes and volume groups and instruct the lvmetad daemon to update its cached state accordingly

[--commandprofile ProfileName]

[-d|--debug]调试模式

[-h|--help]查看帮助信息

[--ignorelockingfailure]忽略锁定失败的错误。

[--mknodes]Also checks the LVM special files in /dev that are needed for active logical volumes and creates any missing ones and removes unused ones

[-P|--partial]部分模式。将处理不完整的逻辑卷

[-v|--verbose]显示输出详细信息

[--version]查看命名版本信息

pvscan命令介绍：

扫描系统中连接的所有硬盘，列出找到的物理卷列表。

pvscan的参数:

pvscan

[-b|—background]在后台运行这个命令

[--cache [-a|--activate ay] [ DevicePath | --major major --minor minor]...]

[--commandprofile ProfileName]

[-d|—debug]调试模式

{-e|--exported | -n|—novolumegroup}-e 仅显示属于输出卷组的物理卷; -n 仅显示不属于任何卷组的物理卷;

[-h|-?|--help]显示命令的帮助信息

[—ignorelockingfailure]忽略锁定失败的错误。

[-P|—partial]部分模式. 将处理不完整的逻辑卷

[--readonly]

[-s|—short]简短格式输出

[-u|—uuid]显示输出UUID信息

[-v|—verbose]显示输出详细信息

[—version]查看pvscan命令版本

lvscan命令介绍 ：

扫描当前系统中存在的所有LVM的逻辑卷(lv)

lvscan的参数：

[-a|—all]输出所有的逻辑卷信息

[-b|--blockdevice]显示逻辑卷的主设备号和次设备号

[--cache]

[--commandprofile ProfileName]

[-d|—debug]调试模式

[-h|-?|--help]查看命令的帮助信息

[——ignorelockingfailure]忽略锁定失败的错误。

[-P|—partial]部分模式. 将处理不完整的逻辑卷

[--readonly]

[-v|—verbose]输出详细的结果

[—version]查看lvscan命令版本

[root@getlnx20 ~]# vgscan

Reading all physical volumes. This may take a while...

Found volume group "VolGroup00" using metadata type lvm2

[root@getlnx20 ~]# pvscan

PV /dev/sda2 VG VolGroup00 lvm2 [39.51 GiB / 0 free]

Total: 1 [39.51 GiB] / in use: 1 [39.51 GiB] / in no VG: 0 [0 ]

[root@getlnx20 ~]# lvscan

ACTIVE '/dev/VolGroup00/lv_root' [31.51 GiB] inherit

ACTIVE '/dev/VolGroup00/lv_swap' [8.00 GiB] inherit

[root@getlnx20 ~]# df -h

Filesystem Size Used Avail Use% Mounted on

/dev/mapper/VolGroup00-lv_root

31G 2.5G 27G 9% /

tmpfs 3.9G 0 3.9G 0% /dev/shm

/dev/sda1 477M 33M 419M 8% /boot

[root@getlnx20 ~]#

新增一块硬盘后，使用fdisk -l命令，我们可以看到这块新增的硬盘被标记为/dev/sdb

[root@getlnx20 ~]# fdisk -l

Disk /dev/sda: 42.9 GB, 42949672960 bytes

64 heads, 32 sectors/track, 40960 cylinders

Units = cylinders of 2048 * 512 = 1048576 bytes

Sector size (logical/physical): 512 bytes / 512 bytes

I/O size (minimum/optimal): 512 bytes / 512 bytes

Disk identifier: 0x0006822c

Device Boot Start End Blocks Id System

/dev/sda1 * 2 501 512000 83 Linux

Partition 1 does not end on cylinder boundary.

/dev/sda2 502 40960 41430016 8e Linux LVM

Partition 2 does not end on cylinder boundary.

Disk /dev/mapper/VolGroup00-lv_root: 33.8 GB, 33831256064 bytes

255 heads, 63 sectors/track, 4113 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/mapper/VolGroup00-lv_swap: 8589 MB, 8589934592 bytes

255 heads, 63 sectors/track, 1044 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/sdb: 85.9 GB, 85899345920 bytes

255 heads, 63 sectors/track, 10443 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

新增一个80G的硬盘，但是为什么使用fdisk -l命令查看到的是85.9G?相信很多人看到这个都会有些疑惑。这个是因为计算时使用的单位有所差异所致， 85899345920/1024/1024/1024=80G，而85899345920/1000/1000/1000 ~= 85.899 ~= 85.9G 。

2： 新建一个分区(partition)

新建一个主分区(primary partition)或逻辑分区(logical partition)都OK

[root@getlnx20 ~]# 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 0xaa12f277.

Changes will remain in memory only, until you decide to write them.

After that, of course, the previous content won't be recoverable.

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

WARNING: DOS-compatible mode is deprecated. It's 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 (1-10443, default 1): 1

Last cylinder, +cylinders or +size{K,M,G} (1-10443, default 10443):

Using default value 10443

Command (m for help): w

The partition table has been altered!

Calling ioctl() to re-read partition table.

Syncing disks.

3：创建PV(物理卷)

[root@getlnx20 ~]# pvcreate /dev/sdb1

Physical volume "/dev/sdb1" successfully created

[root@getlnx20 ~]# pvscan

PV /dev/sda2 VG VolGroup00 lvm2 [39.51 GiB / 0 free]

PV /dev/sdb1 lvm2 [80.00 GiB]

Total: 2 [119.51 GiB] / in use: 1 [39.51 GiB] / in no VG: 1 [80.00 GiB]

4：创建VG(卷组)

[root@getlnx20 ~]# vgcreate -s 32M VolGroup01 /dev/sdb1

Volume group "VolGroup01" successfully created

[root@getlnx20 ~]# vgscan

Reading all physical volumes. This may take a while...

Found volume group "VolGroup01" using metadata type lvm2

Found volume group "VolGroup00" using metadata type lvm2

5：查看VG可用空间

[root@getlnx20 ~]# vgdisplay

--- Volume group ---

VG Name VolGroup01

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

Max PV 0

Cur PV 1

Act PV 1

VG Size 79.97 GiB

PE Size 32.00 MiB

Total PE 2559

Alloc PE / Size 0 / 0

Free PE / Size 2559 / 79.97 GiB

VG UUID FD5kEp-a9Cv-K181-Xb7e-i8k4-zV52-Dbuxc3

--- Volume group ---

VG Name VolGroup00

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 39.51 GiB

PE Size 4.00 MiB

Total PE 10114

Alloc PE / Size 10114 / 39.51 GiB

Free PE / Size 0 / 0

VG UUID sWwXef-0AHf-66ZI-dZHh-JuJt-KMj7-YqIisW

[root@getlnx20 ~]#

6：建立逻辑卷(LV)

[root@getlnx20 ~]# lvcreate -L79.97G -n LogVol00 VolGroup01

Rounding up size to full physical extent 80.00 GiB

Volume group "VolGroup01" has insufficient free space (2559 extents): 2560 required.

[root@getlnx20 ~]# lvcreate -L79.96G -n LogVol00 VolGroup01

Rounding up size to full physical extent 79.97 GiB

Logical volume "LogVol00" created

[root@getlnx20 ~]# lvscan

ACTIVE '/dev/VolGroup01/LogVol00' [79.97 GiB] inherit

ACTIVE '/dev/VolGroup00/lv_root' [31.51 GiB] inherit

ACTIVE '/dev/VolGroup00/lv_swap' [8.00 GiB] inheri

7：建立文件系统

[root@getlnx20 ~]# mkfs -t ext3 /dev/VolGroup01/LogVol00

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

5242880 inodes, 20963328 blocks

1048166 blocks (5.00%) reserved for the super user

First data block=0

Maximum filesystem blocks=4294967296

640 block groups

32768 blocks per group, 32768 fragments per group

8192 inodes per group

Superblock backups stored on blocks:

32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,

4096000, 7962624, 11239424, 20480000

Writing inode tables: done

Creating journal (32768 blocks): done

Writing superblocks and filesystem accounting information: done

This filesystem will be automatically checked every 24 mounts or

180 days, whichever comes first. Use tune2fs -c or -i to override.

8：建立挂载点

[root@getlnx20 ~]# mkdir /mysqldata

9：挂载存储

[root@getlnx20 ~]# mount /dev/VolGroup01/LogVol00 /mysqldata

[root@getlnx20 ~]# df -h

Filesystem Size Used Avail Use% Mounted on

/dev/mapper/VolGroup00-lv_root

31G 2.5G 27G 9% /

tmpfs 3.9G 0 3.9G 0% /dev/shm

/dev/sda1 477M 33M 419M 8% /boot

/dev/mapper/VolGroup01-LogVol00

79G 184M 75G 1% /mysqldata

[root@getlnx20 ~]#

10：修改fstab配置文件实现自动挂载

[root@getlnx20 ~]# more /etc/fstab

#

# /etc/fstab

# Created by anaconda on Sat Jun 13 10:29:07 2015

#

# 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

#

/dev/mapper/VolGroup00-lv_root / ext4 defaults 1 1

UUID=5486634e-ec6a-42d5-bbb9-dcd92537c294 /boot ext4 defaults 1 2

/dev/mapper/VolGroup00-lv_swap swap swap defaults 0 0

/dev/VolGroup01/LogVol00 /mysqldata ext3 defaults 1 1

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

[root@getlnx20 ~]#