Centos/Ubuntu Linux 系统 根目录扩容方法

一、背景

系统根目录空间少或者是通过模板做出来机器，只能按当初模板设置好的大小，超出了大小就需要给根目录做扩容

二、扩容方法

2.1、查看系统盘

• 可以看到 vda 是 200G vda2 根分区是 99G 因为机器是通过模板部署出来的

root@aka:~$ lsblk
NAME            MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
vdb             252:16   0   64M  0 disk
└─vdb1          252:17   0   63M  0 part
sr0              11:0    1 1024M  0 rom
vda             252:0    0  200G  0 disk
├─vda2          252:2    0   99G  0 part
│ ├─centos-swap 253:1    0    2G  0 lvm
│ └─centos-root 253:0    0   97G  0 lvm  /
└─vda1          252:1    0    1G  0 part /boot

2.2、创建分区

• 1、创建主分区
• 2、修改分区格式
• 3、保存分区
• 4、重启系统

root@aka:~$ fdisk /dev/vda
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.
# 输入 n 创建分区
Command (m for help): n
Partition type:
   p   primary (2 primary, 0 extended, 2 free)
   e   extended
# 输入 p 创建主分区
Select (default p): p
# 根据提示输入，不确定下面直接回车也行，因为只能穿件4个主分区已经创建2和主分区，那么现在是第3个主分区，使用我填的是3
Partition number (3,4, default 3): 3
First sector (209715200-419430399, default 209715200):
Using default value 209715200
Last sector, +sectors or +size{K,M,G} (209715200-419430399, default 419430399):
Using default value 419430399
Partition 3 of type Linux and of size 100 GiB is set
# 更改分区格式
Command (m for help): t
# 输入刚才创建分区，1-3说明已经有3个主分区，第三个就是刚刚创建的所以输入 3
Partition number (1-3, default 3): 3
# 输入 8e 将分区改为 Linux LVM
Hex code (type L to list all codes): 8e
Changed type of partition 'Linux' to 'Linux LVM'
# 打印创建好的分区 /dev/vda3 就是刚刚创建好的分区
Command (m for help): p
Disk /dev/vda: 214.7 GB, 214748364800 bytes, 419430400 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: 0x000afaac
   Device Boot      Start         End      Blocks   Id  System
/dev/vda1   *        2048     2099199     1048576   83  Linux
/dev/vda2         2099200   209715199   103808000   8e  Linux LVM
/dev/vda3       209715200   419430399   104857600   8e  Linux LVM
# 输入 w 保存分区，下面报错信息没关系
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.

2.3、创建物理卷

• 创建好的分区必须要重启系统才可以下面步骤
• 已知 /dev/vda3 是刚刚创建好的分区

root@aka:~$ pvcreate /dev/vda3
  Physical volume "/dev/vda3" successfully created

2.4、查看新建的物理卷和大小

• 记住需要扩展的分区 /dev/vda2
• VG Name 为 centos

root@aka:~$ pvdisplay
  --- Physical volume ---
  PV Name               /dev/vda2
  VG Name               centos
  PV Size               <99.00 GiB / not usable 3.00 MiB
  Allocatable           yes
  PE Size               4.00 MiB
  Total PE              25343
  Free PE               1
  Allocated PE          25342
  PV UUID               n1wTfe-5Meu-I0tc-Xmzk-ylLB-aGXM-8fL4eq
  "/dev/vda3" is a new physical volume of "100.00 GiB"
  --- NEW Physical volume ---
  PV Name               /dev/vda3
  VG Name
  PV Size               100.00 GiB
  Allocatable           NO
  PE Size               0
  Total PE              0
  Free PE               0
  Allocated PE          0
  PV UUID               eL8EFo-CAqp-jJea-R9jS-rfEM-bMH0-RWkf9T

2.5、添加物理卷组

• 记住需要扩展的分区 /dev/vda2
• VG Name 为 centos
• 将 /dev/vda3 添加到 centos 卷上

root@aka:~$ vgextend centos /dev/vda3
  Volume group "centos" successfully extended

2.6、查看卷组信息

root@aka:~$ 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               1
  Max PV                0
  Cur PV                2
  Act PV                2
  VG Size               198.99 GiB
  PE Size               4.00 MiB
  Total PE              50942
  Alloc PE / Size       25342 / 98.99 GiB
  Free  PE / Size       25600 / 100.00 GiB
  VG UUID               tzm4di-Vz3A-cNQa-fjdS-bHaV-5FJW-PnVlAG

2.7、卷组扩容

• /dev/mapper/centos-root 通过 df -h 看看系统根目录，这个是啥就填写啥
• 使用 lvextend -l +100%FREE /dev/mapper/centos-root 将空间全部扩容到 /dev/mapper/centos-root 逻辑卷中

root@aka:~$ lvextend -l +100%FREE /dev/mapper/centos-root
  Size of logical volume centos/root changed from <97.00 GiB (24831 extents) to <197.00 GiB (50431 extents).
  Logical volume centos/root successfully resized

2.8、查看文件系统

• 这里有个区别 需要自己看自己文件系统是啥 ext4 和 xfs
• 我这里文件系统是 xfs

root@aka3:~$ cat /etc/fstab
/dev/mapper/centos-root /                       xfs     defaults        0 0
UUID=ddb55cda-6a30-41af-9f0c-acb092eb7178 /boot                   xfs     defaults        0 0
/dev/mapper/centos-swap swap                    swap    defaults        0 0

2.9、刷新文件系统使扩容生效

• 注意：如果文件系统是 ext4 格式用 resize2fs ，我这里是 xfs 格式用 xfs_growfs

1) xfs 文件系统方法

root@aka:~$ xfs_growfs /dev/mapper/centos-root
meta-data=/dev/mapper/centos-root isize=512    agcount=4, agsize=6356736 blks
         =                       sectsz=512   attr=2, projid32bit=1
         =                       crc=1        finobt=0 spinodes=0
data     =                       bsize=4096   blocks=25426944, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0 ftype=1
log      =internal               bsize=4096   blocks=12415, version=2
         =                       sectsz=512   sunit=0 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0
data blocks changed from 25426944 to 51641344

2) ext4 文件系统方法

resize2fs /dev/mapper/centos-root

2.10、查看扩容是否成功

• 到这里扩容完成

root@aka:~$ df -h
Filesystem               Size  Used Avail Use% Mounted on
devtmpfs                  12G     0   12G   0% /dev
tmpfs                     12G     0   12G   0% /dev/shm
tmpfs                     12G  9.6M   12G   1% /run
tmpfs                     12G     0   12G   0% /sys/fs/cgroup
/dev/mapper/centos-root  197G   15G  183G   8% /
/dev/vda1               1014M  201M  814M  20% /boot