How to create a LVM group from two hard disk partitions is introduced in this post.

本文介绍了如何从两个硬盘分区创建LVM组。

Assume we have installed two hard disks /dev/sdb and /dev/sdc to the server, our task now is to create one LVM volume group vg_xen for installing LVM backed Xen DomUs from these two disks. We will do this by several steps: create partitions on the hard disks, initialize disk partitions and create a volume group.

假设我们已经在服务器上安装了两个硬盘/ dev / sdb和/ dev / sdc，我们现在的任务是创建一个LVM卷组vg_xen，以从这两个磁盘安装LVM支持的Xen DomU 。 我们将通过几个步骤来执行此操作：在硬盘上创建分区，初始化磁盘分区并创建卷组。

在硬盘上创建分区 (Create partitions on the hard disks)

We can use fdisk to create partitions:

我们可以使用fdisk创建分区：

# fdisk /dev/sdb

Add a new partition by command: n

通过命令添加新分区：n

Select primary partition by: p

通过以下方式选择主分区：p

Select partition number 1: 1

选择分区号1：1

Then select from the first section to the last one.

然后从第一部分选择最后一部分。

Write table to disk and exit by command: w

将表写入磁盘并通过命令退出：w

We can find out the new partition in /dev/ directory:

我们可以在/ dev /目录中找到新分区：

$ ls /dev/sd*

We can find:

我们可以找：

/dev/sdb1

Follow the same procedure to create partition /dev/sdc1

按照相同的步骤创建分区/ dev / sdc1

初始化磁盘分区 (Initialize disk partitions)

Create volume group descriptors at the starts of partitions:

在分区的开头创建卷组描述符：

    # pvcreate /dev/sdb1
    # pvcreate /dev/sdc1

创建一个卷组 (Create a volume group)

We create LVM volume group vg_xen that contains /dev/sdb1 and /dev/sdc1:

我们创建包含/ dev / sdb1和/ dev / sdc1的LVM卷组vg_xen：

# vgcreate vg_xen /dev/sdb1 /dev/sdc1

激活新添加的音量组 (Activate the new added volume group)

We can activeate it by scan the volume groups:

我们可以通过扫描卷组来激活它：

# vgscan

将新的物理卷添加到卷组 (Add new physical volumes to the volume group)

If we installed another hard disk /dev/sdd afterwards, we can create partition /dev/sdd1 on it and initialize it as introduced above. Then we can add the new physical volume to the volume group:

如果之后再安装另一个硬盘/ dev / sdd，则可以在其上创建分区/ dev / sdd1并按照上面的介绍对其进行初始化。 然后，我们可以将新的物理卷添加到卷组中：

# vgextend vg_xen /dev/sdd1

A more detailed tutorial of extending a LVM volume group can be found here: Extending a LVM Volume Group.

更详细的教程的延伸的LVM卷组可以在这里找到： 扩展LVM卷组 。

翻译自: https://www.systutorials.com/creating-lvm-volume-group/

[root@localhost ~]# df -h
文件系统                 容量  已用  可用 已用% 挂载点
devtmpfs                 475M     0  475M    0% /dev
tmpfs                    487M     0  487M    0% /dev/shm
tmpfs                    487M  7.6M  479M    2% /run
tmpfs                    487M     0  487M    0% /sys/fs/cgroup
/dev/mapper/centos-root   17G  2.3G   15G   14% /
/dev/sr0                 4.5G  4.5G     0  100% /iso
/dev/sda1               1014M  137M  878M   14% /boot
tmpfs                     98M     0   98M    0% /run/user/0

[root@localhost ~]# fdisk -l /dev/sdb /dev/sdc

磁盘 /dev/sdb：5368 MB, 5368709120 字节，10485760 个扇区
Units = 扇区 of 1 * 512 = 512 bytes
扇区大小(逻辑/物理)：512 字节 / 512 字节
I/O 大小(最小/最佳)：512 字节 / 512 字节


磁盘 /dev/sdc：5368 MB, 5368709120 字节，10485760 个扇区
Units = 扇区 of 1 * 512 = 512 bytes
扇区大小(逻辑/物理)：512 字节 / 512 字节
I/O 大小(最小/最佳)：512 字节 / 512 字节

3、将sdb和sdc创建物理卷，返回创建物理卷成功；注：硬盘可以一块或多块，也可使用格式为8e的分区创建物理卷

[root@localhost ~]# pvcreate /dev/sdb /dev/sdc
  Physical volume "/dev/sdb" successfully created.
  Physical volume "/dev/sdc" successfully created.

4、查看一下物理卷的信息；

[root@localhost ~]# pvdisplay
 "/dev/sdc" is a new physical volume of "5.00 GiB"
  --- NEW Physical volume ---
  PV Name               /dev/sdc
  VG Name
  PV Size               5.00 GiB
  Allocatable           NO
  PE Size               0
  Total PE              0
  Free PE               0
  Allocated PE          0
  PV UUID               FddYEs-ANMR-pgBg-AHMY-I6B9-2LIq-jNjaTh

  "/dev/sdb" is a new physical volume of "5.00 GiB"
  --- NEW Physical volume ---
  PV Name               /dev/sdb
  VG Name
  PV Size               5.00 GiB
  Allocatable           NO
  PE Size               0
  Total PE              0
  Free PE               0
  Allocated PE          0
  PV UUID               00PzWu-qstD-xHRC-vzjf-X27D-lu4u-2rn1x8

5、查看根分区的卷组名称VG name，可以看到为centos；

[root@localhost ~]# vgdisplay
  --- Volume group ---
  VG Name               centos
  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               <19.00 GiB
  PE Size               4.00 MiB
  Total PE              4863
  Alloc PE / Size       4863 / <19.00 GiB
  Free  PE / Size       0 / 0
  VG UUID               HfWWKM-EgcF-g40V-39zT-ghys-uihW-dMHbzb

6、将sdb和sdc添加到名称为centos的卷组，可以看到返回添加成功；

[root@localhost ~]# vgextend centos /dev/sdb /dev/sdc
  Volume group "centos" successfully extended

7、查看逻辑卷信息；

[root@localhost ~]# lvdisplay
  --- Logical volume ---
  LV Path                /dev/centos/root
  LV Name                root
  VG Name                centos
  LV UUID                dbTv5f-WGBj-rF2W-ZDAk-4cwS-fZKI-egTr7u
  LV Write Access        read/write
  LV Creation host, time 192.168.133.128, 2021-01-17 22:18:54 +0800
  LV Status              available
  # open                 1
  LV Size                <17.00 GiB
  Current LE             4351
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     8192
  Block device           253:0

8、将卷组全部剩余空间添加至逻辑卷；

[root@localhost ~]# lvextend -l +100%FREE /dev/centos/root
  Size of logical volume centos/root changed from <17.00 GiB (4351 extents) to <26.99 GiB (6909 extents).
  Logical volume centos/root successfully resized.

9、执行根分区刷新；

[root@localhost ~]# xfs_growfs /dev/centos/root

10、查看扩容后的根分区空间大小，已经为27G；

[root@localhost ~]# df -h
文件系统                 容量  已用  可用 已用% 挂载点
devtmpfs                 475M     0  475M    0% /dev
tmpfs                    487M     0  487M    0% /dev/shm
tmpfs                    487M  7.6M  479M    2% /run
tmpfs                    487M     0  487M    0% /sys/fs/cgroup
/dev/mapper/centos-root   27G  2.3G   25G    9% /
/dev/sr0                 4.5G  4.5G     0  100% /iso
/dev/sda1               1014M  137M  878M   14% /boot
tmpfs                     98M     0   98M    0% /run/user/0

四、创建LVM卷挂载目录

1、还是以sdb和sdc为例；

[root@localhost ~]# pvcreate /dev/sdb /dev/sdc
  Physical volume "/dev/sdb" successfully created.
  Physical volume "/dev/sdc" successfully created.

2、创建卷组，vgcreate  卷组名称   /dev/sdb  /dev/sdc；

[root@localhost ~]# vgcreate vgtest /dev/sdb /dev/sdc
  Volume group "vgtest" successfully created

3、查看卷组信息；

[root@localhost ~]# vgdisplay
--- Volume group ---
  VG Name               vgtest
  System ID
  Format                lvm2
  Metadata Areas        2
  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                2
  Act PV                2
  VG Size               9.99 GiB
  PE Size               4.00 MiB
  Total PE              2558
  Alloc PE / Size       0 / 0
  Free  PE / Size       2558 / 9.99 GiB
  VG UUID               JRwmiW-TcAS-558L-oRB4-k0pV-nDeK-bq8W3R

4、创建逻辑卷，lvcreate  -l  100%FREE  卷组名称  -n  逻辑卷名称；

[root@localhost ~]# lvcreate -l 100%FREE vgtest -n lvtest
  Logical volume "lvtest" created.

5、格式化逻辑卷，可以根据需要选择文件系统格式；

[root@localhost ~]# mkfs -t xfs /dev/vgtest/lvtest

6、挂载逻辑卷；

[root@localhost ~]# mount /dev/vgtest/lvtest /lvtest/

7、df查看已挂载成功；

[root@localhost ~]# df -h
文件系统                   容量  已用  可用 已用% 挂载点
devtmpfs                   475M     0  475M    0% /dev
tmpfs                      487M     0  487M    0% /dev/shm
tmpfs                      487M  7.6M  479M    2% /run
tmpfs                      487M     0  487M    0% /sys/fs/cgroup
/dev/mapper/centos-root     17G  2.3G   15G   14% /
/dev/sr0                   4.5G  4.5G     0  100% /iso
/dev/sda1                 1014M  137M  878M   14% /boot
tmpfs                       98M     0   98M    0% /run/user/0
/dev/mapper/vgtest-lvtest   10G   33M   10G    1% /lvtest