如何在KVM虚拟机中扩展LVM磁盘

KVM中增加磁盘作为扩展

创建空磁盘

通过qemu-img 命令创建qcow2的磁盘,也可以创建其他类型的磁盘,但扩展磁盘的时候,在kvm里面的命令有所区别

[root@server10 ~]# qemu-img create -f qcow2 /opt/extern.qcow2 100G
Formatting '/opt/extern.qcow2', fmt=qcow2 size=107374182400 encryption=off 

[root@server10 opt]# qemu-img info extern.qcow2
image: extern.qcow2
file format: qcow2
virtual size: 100G (107374182400 bytes)
disk size: 294M
cluster_size: 65536
Format specific information:
    compat: 1.1
    lazy refcounts: false

热挂载磁盘 ,注意,增加磁盘必须使用-subdriver,否则不认识kvm内部不认识磁盘

直接挂载磁盘到虚拟机.虚拟机需要在运行状态可直接看到有其他硬盘被挂载

[root@server10 opt]# virsh attach-disk centos7V1-bigdata /opt/extern.qcow2 vdb  --subdriver=qcow2 --persistent

virsh help  attach-disk
  NAME
    attach-disk - attach disk device

  SYNOPSIS
    attach-disk [--targetbus ] [--driver ] [--subdriver ] [--iothread ] [--cache ] [--io ] [--type ] [--mode ] [--sourcetype ] [--serial ] [--wwn ] [--rawio] [--address ] [--multifunction] [--print-xml] [--persistent] [--config] [--live] [--current]

  DESCRIPTION
    Attach new disk device.

  OPTIONS
    [--domain]  domain name, id or uuid
    [--source]  source of disk device
    [--target]  target of disk device
    --targetbus  target bus of disk device
    --driver  driver of disk device
    --subdriver  subdriver of disk device
    --iothread  IOThread to be used by supported device
    --cache  cache mode of disk device
    --io    io policy of disk device
    --type  target device type
    --mode  mode of device reading and writing
    --sourcetype  type of source (block|file)
    --serial  serial of disk device
    --wwn   wwn of disk device
    --rawio          needs rawio capability
    --address  address of disk device
    --multifunction  use multifunction pci under specified address
    --print-xml      print XML document rather than attach the disk
    --persistent     make live change persistent
    --config         affect next boot
    --live           affect running domain
    --current        affect current domain
 

创建分区 

选择卷标必须使用8e,这个表示是LVM磁盘格式

[root@localhost ~]# fdisk /dev/vdc
Welcome to fdisk (util-linux 2.23.2).

Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.

Device does not contain a recognized partition table
Building a new DOS disklabel with disk identifier 0x14401f11.

Command (m for help): n
Partition type:
   p   primary (0 primary, 0 extended, 4 free)
   e   extended
Select (default p): p
Partition number (1-4, default 1): 1
First sector (2048-209715199, default 2048):
Using default value 2048
Last sector, +sectors or +size{K,M,G} (2048-209715199, default 209715199):
Using default value 209715199
Partition 1 of type Linux and of size 100 GiB is set

Command (m for help): t
Selected partition 1
Hex code (type L to list all codes): 8e
Changed type of partition 'Linux' to 'Linux LVM'

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

Calling ioctl() to re-read partition table.
[38384.918771]  vdc: vdc1
Syncing disks.
[root@localhost ~]# [38384.934024]  vdc: vdc1

我们进入虚拟机系统,然后看下系统硬盘的情况,可以看到硬盘已经被虚拟机监测到.

[root@localhost ~]# fdisk -l

Disk /dev/vda: 10.7 GB, 10737418240 bytes, 20971520 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 label type: dos
Disk identifier: 0x000be9e1

   Device Boot      Start         End      Blocks   Id  System
/dev/vda1   *        2048     2099199     1048576   83  Linux
/dev/vda2         2099200    20971519     9436160   8e  Linux LVM

Disk /dev/vdb: 107.4 GB, 107374182400 bytes, 209715200 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 label type: dos
Disk identifier: 0x8e9d6aff

   Device Boot      Start         End      Blocks   Id  System
/dev/vdb1            2048   209715199   104856576   8e  Linux LVM

创建PV

从物理磁盘创建LVM磁盘分区.

[root@localhost ~]# pvcreate /dev/vdb
  Physical volume "/dev/vdb1" successfully created.

创建VG

VG是逻辑卷,可以容纳很多PE,以后可以扩展VG达到增长磁盘大小的作用,这里我们命名逻辑卷名称VolGroup01

[root@localhost ~]# vgcreate VolGroup01 /dev/vdb1
  Volume group "VolGroup01" successfully created

创建LV

LV是真正分给应用程序使用的分区,属于VG.在VG容量许可的情况下,LV可以自己扩展大小,

[root@localhost ~]# lvcreate -L 10G -n lv01 VolGroup01
  Logical volume "lv01" created.

查看LV信息

[root@localohst ~]# lvdisplay 
 --- Logical volume ---
  LV Path                /dev/centos/root
  LV Name                root
  VG Name                centos
  LV UUID                JrHsb3-E9Ym-Rh79-iosJ-hzHJ-ylPD-Gcc4Co
  LV Write Access        read/write
  LV Creation host, time localhost, 2020-12-23 18:47:47 +0800
  LV Status              available
  # open                 1
  LV Size                10 GiB
  Current LE             11047
  Segments               2
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     8192
  Block device           253:0

  --- Logical volume ---
  LV Path                /dev/VolGroup01/lv01
  LV Name                lv01
  VG Name                VolGroup01
  LV UUID                Fjk4G9-g2rP-W8h4-JEEF-2q3F-kykM-cjBoMt
  LV Write Access        read/write
  LV Creation host, time localhost.localdomain, 2021-04-04 23:30:12 +0800
  LV Status              available
  # open                 0
  LV Size                10.00 GiB
  Current LE             2560
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     8192
  Block device           253:2

格式化 

[root@localhost ~]# mkfs -t ext4  /dev/VolGroup01/lv01
mke2fs 1.42.9 (28-Dec-2013)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
655360 inodes, 2621440 blocks
131072 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=2151677952
80 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

Allocating group tables: done
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information:
done

挂载
 

[root@localhost ~]# mkdir /extend
[root@localhost ~]# mount /dev/VolGroup01/lv01 /extend
[  498.219610] EXT4-fs (dm-2): mounted filesystem with ordered data mode. Opts: (null)
[root@localhost ~]# cd /extend/
[root@localhost extend]# ls
lost+found
[root@localhost extend]# df -k
Filesystem                  1K-blocks    Used Available Use% Mounted on
devtmpfs                       894512       0    894512   0% /dev
tmpfs                          906156       0    906156   0% /dev/shm
tmpfs                          906156    8664    897492   1% /run
tmpfs                          906156       0    906156   0% /sys/fs/cgroup
/dev/mapper/centos-root       8374272 3695940   4678332  45% /
/dev/vda1                     1038336  196740    841596  19% /boot
tmpfs                          181232       0    181232   0% /run/user/0
/dev/mapper/VolGroup01-lv01  10190100   36888   9612540   1% /extend

KVM中直接扩展磁盘

直接扩展磁盘就是扩大系统原有的逻辑分区,而不要将新的磁盘直接挂载到某个目录.这种方法应该更加流畅.

创建磁盘,注意,增加磁盘必须使用-subdriver,否则不认识kvm内部不认识磁盘

[root@server10 opt]# qemu-img create -f qcow2 /opt/vgextend.qcow2 100G
Formatting '/opt/vgextend.qcow2', fmt=qcow2 size=107374182400 encryption=off cluster_size=65536 lazy_refcounts=off

[root@server10 opt]# virsh attach-disk centos7V1-bigdata /opt/vgextend.qcow2 vdc  --subdriver=qcow2

 创建分区(注意使用8e)

[root@localhost ~]# fdisk /dev/vdc
Welcome to fdisk (util-linux 2.23.2).

Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.

Device does not contain a recognized partition table
Building a new DOS disklabel with disk identifier 0x14401f11.

Command (m for help): n
Partition type:
   p   primary (0 primary, 0 extended, 4 free)
   e   extended
Select (default p): p
Partition number (1-4, default 1): 1
First sector (2048-209715199, default 2048):
Using default value 2048
Last sector, +sectors or +size{K,M,G} (2048-209715199, default 209715199):
Using default value 209715199
Partition 1 of type Linux and of size 100 GiB is set

Command (m for help): t
Selected partition 1
Hex code (type L to list all codes): 8e
Changed type of partition 'Linux' to 'Linux LVM'

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

Calling ioctl() to re-read partition table.
[38384.918771]  vdc: vdc1
Syncing disks.
[root@localhost ~]# [38384.934024]  vdc: vdc1

查看分区 

到KVM虚拟机内部,查看下需要扩展的磁盘,使用命令vgdisplay,我们扩展centos逻辑分区

[root@localhost ~]# vgdisplay
  --- Volume group ---
  VG Name               centos
  System ID
  Format                lvm2
  Metadata Areas        2
  Metadata Sequence No  4
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                2
  Open LV               2
  Max PV                0
  Cur PV                2
  Act PV                2
  VG Size               10 GiB
  PE Size               4.00 MiB
  Total PE              27902
  Alloc PE / Size       2303 / <9.00 GiB
  Free  PE / Size       25599 / <100.00 GiB
  VG UUID               DHsBK6-fe7b-n4V2-H5Lx-1p1g-oaPI-HWwS6k

  --- Volume group ---
  VG Name               VolGroup01
  System ID
  Format                lvm2
  Metadata Areas        1
  Metadata Sequence No  2
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                1
  Open LV               0
  Max PV                0
  Cur PV                1
  Act PV                1
  VG Size               <100.00 GiB
  PE Size               4.00 MiB
  Total PE              25599
  Alloc PE / Size       2560 / 10.00 GiB
  Free  PE / Size       23039 / <90.00 GiB
  VG UUID               OIaURj-GFML-uhcA-ibgz-9tZg-OPfP-Obtak5

扩展VG组

[root@localhost ~]# vgextend centos /dev/vdc
  Physical volume "/dev/vdc" successfully created.
  Volume group "centos" successfully extended

再查看分期,看到VG的大小已经扩大,就是说包含了我们刚才创建的磁盘.

[root@localhost ~]# vgdisplay
  --- Volume group ---
  VG Name               centos
  System ID
  Format                lvm2
  Metadata Areas        2
  Metadata Sequence No  4
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                2
  Open LV               2
  Max PV                0
  Cur PV                2
  Act PV                2
  VG Size               108.99 GiB
  PE Size               4.00 MiB
  Total PE              27902
  Alloc PE / Size       2303 / <9.00 GiB
  Free  PE / Size       25599 / <100.00 GiB
  VG UUID               DHsBK6-fe7b-n4V2-H5Lx-1p1g-oaPI-HWwS6k

  --- Volume group ---
  VG Name               VolGroup01
  System ID
  Format                lvm2
  Metadata Areas        1
  Metadata Sequence No  2
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                1
  Open LV               0
  Max PV                0
  Cur PV                1
  Act PV                1
  VG Size               <100.00 GiB
  PE Size               4.00 MiB
  Total PE              25599
  Alloc PE / Size       2560 / 10.00 GiB
  Free  PE / Size       23039 / <90.00 GiB
  VG UUID               OIaURj-GFML-uhcA-ibgz-9tZg-OPfP-Obtak5

扩展逻辑分区

扩展好了默认系统不会立刻有效果

[root@localhost ~]# lvextend -l +9000 /dev/centos/root (9000是柱面)
  Size of logical volume centos/root changed from <8.00 GiB (2047 extents) to 43.15 GiB (11047 extents).
  Logical volume centos/root successfully resized.

# 上述命令也可以使用 -L 30000m表示增加30G空间

继续更改大小

使用resize2fs 继续查看 ,发现没增加,实际上系统目前用的是xfs系统,使用xfs_growfs命令会看到系root分区扩大成功

[root@localhost ~]# resize2fs /dev/centos/root 
resize2fs 1.42.9 (28-Dec-2013)
resize2fs: Bad magic number in super-block while trying to open /dev/centos/root
Couldn't find valid filesystem superblock.
[root@localhost ~]# mount |grep root
/dev/mapper/centos-root on / type xfs (rw,relatime,seclabel,attr2,inode64,noquota)
[root@localhost ~]# xfs_growfs /dev/mapper/centos-root
meta-data=/dev/mapper/centos-root isize=512    agcount=4, agsize=524032 blks
         =                       sectsz=512   attr=2, projid32bit=1
         =                       crc=1        finobt=0 spinodes=0
data     =                       bsize=4096   blocks=2096128, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0 ftype=1
log      =internal               bsize=4096   blocks=2560, version=2
         =                       sectsz=512   sunit=0 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0
data blocks changed from 2096128 to 11312128
[root@localhost ~]# df -Th
Filesystem              Type      Size  Used Avail Use% Mounted on
devtmpfs                devtmpfs  874M     0  874M   0% /dev
tmpfs                   tmpfs     885M     0  885M   0% /dev/shm
tmpfs                   tmpfs     885M  8.5M  877M   1% /run
tmpfs                   tmpfs     885M     0  885M   0% /sys/fs/cgroup
/dev/mapper/centos-root xfs        44G  3.6G   40G   9% /
/dev/vda1               xfs      1014M  193M  822M  19% /boot
tmpfs                   tmpfs     177M     0  177M   0% /run/user/0

更改完成