Linux LVM partition

Volumegroups

Volume groups are nothing but a pool of storage that consists of one or more physical volumes. Once you create the physical volume, you can create the volume group (VG) from these physical volumes (PV).

# -*- mode: ruby -*-
# vi: set ft=ruby :

Vagrant.configure("2") do |config|
  config.vm.box = "centos/7"
  config.vm.define :server1 do |node|
            node.vm.network :private_network, :ip => "10.0.0.10"
            node.vm.network :private_network, :ip => "20.0.0.10"
            node.vm.hostname = "server1.example.com"
            node.vm.provider :libvirt do |domain|
              domain.uri = 'qemu+unix:///system'
              domain.driver = 'kvm'
              domain.memory = 2048
              domain.cpus = 2
              domain.nested = true
              domain.volume_cache = 'none'
              domain.storage :file, :size => '20G'
              domain.storage :file, :size => '20G'
              domain.storage :file, :size => '20G'
            end
  end
  config.vm.define :server2 do |node|
            node.vm.network :private_network, :ip => "10.0.0.11"
            node.vm.network :private_network, :ip => "20.0.0.11"
            node.vm.hostname = "server2.example.com"
            node.vm.provider :libvirt do |domain|
              domain.uri = 'qemu+unix:///system'
              domain.driver = 'kvm'
              domain.memory = 2048
              domain.cpus = 2
              domain.nested = true
              domain.volume_cache = 'none'
            end
  end
end

pvcreate,vgcreate,lvcreate

    vagrant ssh server1
sudo su -
fdisk -l

    // แสดง disk ทีี่เชื่อมกับ server1
    Disk /dev/vdb: 21.5 GB, 21474836480 bytes, 41943040 sectors
    Units = sectors of 1 * 512 = 512 bytes
    Sector size (logical/physical): 512 bytes / 512 bytes
    I/O size (minimum/optimal): 512 bytes / 512 bytes


    Disk /dev/vdc: 21.5 GB, 21474836480 bytes, 41943040 sectors
    Units = sectors of 1 * 512 = 512 bytes
    Sector size (logical/physical): 512 bytes / 512 bytes
    I/O size (minimum/optimal): 512 bytes / 512 bytes


    Disk /dev/vdd: 21.5 GB, 21474836480 bytes, 41943040 sectors
    Units = sectors of 1 * 512 = 512 bytes
    Sector size (logical/physical): 512 bytes / 512 bytes
    I/O size (minimum/optimal): 512 bytes / 512 bytes

//create phisical volume
# pvcreate /dev/vdb
Physical volume "/dev/vdb" successfully created

# pvcreate /dev/vdc
Physical volume "/dev/vdc" successfully created

# pvcreate /dev/vdd
Physical volume "/dev/vdd" successfully created


# vgcreate myvol  /dev/vdb /dev/vdc /dev/vdd
Volume group "myvol" successfully created

ตรวจสอบด้วยคำสั่ง vgdisplay

# vgdisplay

--- Volume group ---
VG Name               myvol
System ID
Format                lvm2
Metadata Areas        3
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                3
Act PV                3
VG Size               59.99 GiB
PE Size               4.00 MiB
Total PE              15357
Alloc PE / Size       0 / 0
Free  PE / Size       15357 / 59.99 GiB
VG UUID               5UZdx5-6m3S-Bh7O-yMWk-A3gS-dJey-N8Ndd1

การใช้งาน volumegroup ได้โดยการแบ่งพื้นที่การใช้งาน ด้วยคำสั่ง lvcreate

            # lvcreate -l 5 -n data1 myvol
    Logical volume "data1" created.

# lvdisplay

    --- Logical volume ---
    LV Path                /dev/myvol/data1
    LV Name                data1
    VG Name                myvol
    LV UUID                cVlf5O-SHa5-hB6Y-pSGK-cXaG-9Yok-bMGIxn
    LV Write Access        read/write
    LV Creation host, time server1, 2016-07-05 02:37:21 -0400
    LV Status              available
    # open                 0
    LV Size                20.00 MiB
    Current LE             5
    Segments               1
    Allocation             inherit
    Read ahead sectors     auto
    - currently set to     8192
    Block device           253:2

Format สร้าง file system และ สร้าง mount point สำหรับการใช้้งาน

            # mkfs.ext4 /dev/myvol/data1
# mkdir /data1
# mount /dev/myvol/data1  /data1
# cd /data1
# touch text.txt