记录一次系统磁盘扩容

1.查看当前系统磁盘使用情况，可知跟分区空间不足5G

[root@master1 ~]# df -h
Filesystem               Size  Used Avail Use% Mounted on
devtmpfs                 1.9G     0  1.9G   0% /dev
tmpfs                    2.0G     0  2.0G   0% /dev/shm
tmpfs                    2.0G   12M  1.9G   1% /run
tmpfs                    2.0G     0  2.0G   0% /sys/fs/cgroup
/dev/mapper/centos-root   19G   15G  2.9G  84% /
/dev/sda2               1014M  175M  840M  18% /boot

2.查看sda分区未分配空间，还剩余30G

[root@master1 ~]# lsblk
NAME            MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sdb               8:16   0   10G  0 disk 
sr0              11:0    1 1024M  0 rom  
sda               8:0    0   50G  0 disk 
├─sda2            8:2    0    1G  0 part /boot
├─sda3            8:3    0   19G  0 part 
│ └─centos-root 253:0    0   19G  0 lvm  /
└─sda1            8:1    0    2M  0 part

3.使用fdisk命令创建新分区sda4，partprobe同步磁盘状态

[root@master1 ~]# fdisk /dev/sda 
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.

Command (m for help): n
Partition type:
   p   primary (3 primary, 0 extended, 1 free)
   e   extended
Select (default e): p
Selected partition 4
First sector (41943040-104857599, default 41943040): 
Using default value 41943040
Last sector, +sectors or +size{K,M,G} (41943040-104857599, default 104857599): +30G
Value out of range.
Last sector, +sectors or +size{K,M,G} (41943040-104857599, default 104857599):         
Using default value 104857599
Partition 4 of type Linux and of size 30 GiB is set

Command (m for help): p

Disk /dev/sda: 53.7 GB, 53687091200 bytes, 104857600 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: 0x0009b521

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1            2048        6143        2048   83  Linux
/dev/sda2   *        6144     2103295     1048576   83  Linux
/dev/sda3         2103296    41943039    19919872   8e  Linux LVM
/dev/sda4        41943040   104857599    31457280   83  Linux

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

Calling ioctl() to re-read partition table.

WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
The kernel still uses the old table. The new table will be used at
the next reboot or after you run partprobe(8) or kpartx(8)
Syncing disks.
[root@master1 ~]# lsblk
NAME            MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sdb               8:16   0   10G  0 disk 
sr0              11:0    1 1024M  0 rom  
sda               8:0    0   50G  0 disk 
├─sda2            8:2    0    1G  0 part /boot
├─sda3            8:3    0   19G  0 part 
│ └─centos-root 253:0    0   19G  0 lvm  /
└─sda1            8:1    0    2M  0 part
[root@master1 ~]# 
[root@master1 ~]# partprobe
[root@master1 ~]# lsblk
NAME            MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sdb               8:16   0   10G  0 disk 
sr0              11:0    1 1024M  0 rom  
sda               8:0    0   50G  0 disk 
├─sda4            8:4    0   30G  0 part 
├─sda2            8:2    0    1G  0 part /boot
├─sda3            8:3    0   19G  0 part 
│ └─centos-root 253:0    0   19G  0 lvm  /
└─sda1            8:1    0    2M  0 part 
[root@master1 ~]#

4.lvm虚拟磁盘扩容

[root@master1 ~]# pvcreate /dev/sda4
  Physical volume "/dev/sda4" successfully created.
[root@master1 ~]# 
[root@master1 ~]# pvs
  PV         VG     Fmt  Attr PSize   PFree 
  /dev/sda3  centos lvm2 a--  <19.00g     0 
  /dev/sda4         lvm2 ---   30.00g 30.00g
[root@master1 ~]# 
[root@master1 ~]# vgextend centos /dev/sda4
  Volume group "centos" successfully extended
[root@master1 ~]# 
[root@master1 ~]# vgs
  VG     #PV #LV #SN Attr   VSize  VFree  
  centos   2   1   0 wz--n- 48.99g <30.00g 
[root@master1 ~]# 
[root@master1 ~]# lvextend -l +100%FREE /dev/centos/root
  Size of logical volume centos/root changed from <19.00 GiB (4863 extents) to 48.99 GiB (12542 extents).
  Logical volume centos/root successfully resized.
[root@master1 ~]# 
[root@master1 ~]# lvs
  LV   VG     Attr       LSize  Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  root centos -wi-ao---- 48.99g                                                    
[root@master1 ~]# 
[root@master1 ~]# resize2fs /dev/centos/root 
resize2fs 1.42.9 (28-Dec-2013)
Filesystem at /dev/centos/root is mounted on /; on-line resizing required
old_desc_blocks = 3, new_desc_blocks = 7
The filesystem on /dev/centos/root is now 12843008 blocks long.
[root@master1 ~]#
[root@master1 ~]# df -h
Filesystem               Size  Used Avail Use% Mounted on
devtmpfs                 1.9G     0  1.9G   0% /dev
tmpfs                    2.0G     0  2.0G   0% /dev/shm
tmpfs                    2.0G   12M  1.9G   1% /run
tmpfs                    2.0G     0  2.0G   0% /sys/fs/cgroup
/dev/mapper/centos-root   49G   15G   32G  32% /
/dev/sda2               1014M  175M  840M  18% /boot

xfs_growfs命令执行错误会有如下提示，执行下resize2fs就可以了哈

[root@master1 ~]# xfs_growfs /dev/centos/root 
xfs_growfs: /dev/centos/root is not a mounted XFS filesystem

ps：lvextend 扩展后只是扩展了lv的大小，而此时文件系统并未感知到，所有还需要使用xfs_growfs、resize2fs等命令来扩展文件系统，xfs_growf命令是扩展xfs文件系统，resize2fs是扩展ext4文件系统。

记录一次系统磁盘扩容

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