centos_home-home空闲空间重新分配到centos_home-root

问题

centos默认安装时对root分区仅仅分配了50G的空间，剩下的都基本上在home分区，宝塔面板默认是在根目录下放置相关网站文件，导致root空间捉襟见肘

解决方法

此方法需要格式化home分区，请提前备份home分区资料

• 查看当前分区状态及分区名称

  [root@home ~]# df -h
  文件系统                      容量  已用  可用 已用% 挂载点
  /dev/mapper/centos_home-root   50G   36G   15G   71% /
  devtmpfs                       16G     0   16G    0% /dev
  tmpfs                          16G  8.0K   16G    1% /dev/shm
  tmpfs                          16G  9.9M   16G    1% /run
  tmpfs                          16G     0   16G    0% /sys/fs/cgroup
  /dev/sda2                    1014M  160M  855M   16% /boot
  /dev/sda1                     200M   12M  189M    6% /boot/efi
  /dev/mapper/centos_home-home  410G   36M  410G    1% /home
  tmpfs                         3.2G     0  3.2G    0% /run/user/0

• 解除挂载

  umount /home

• 执行lvreduce释放home分区多余的空间

  [root@home ~]# lvreduce -L 200G /dev/mapper/centos_home-home
  WARNING: Reducing active and open logical volume to 200.00 GiB.
  THIS MAY DESTROY YOUR DATA (filesystem etc.)
  Do you really want to reduce centos_home/home? [y/n]: y
  Size of logical volume centos_home/home changed from 410.05 GiB (104973 extents) to 200.00 GiB (51200 extents).
  Logical volume centos_home/home successfully resized.

• 将释放出来的空间分配给root

  [root@home ~]# lvextend -l +100%FREE /dev/mapper/centos_home-root
  Size of logical volume centos_home/root changed from 50.00 GiB (12800 extents) to 260.05 GiB (66574 extents).
  Logical volume centos_home/root successfully resized.

• 使用xfs命令使修改生效

  [root@home ~]# xfs_growfs /dev/mapper/centos_home-root
  meta-data=/dev/mapper/centos_home-root isize=512    agcount=4, agsize=3276800 blks
       =                       sectsz=512   attr=2, projid32bit=1
       =                       crc=1        finobt=0 spinodes=0
  data     =                       bsize=4096   blocks=13107200, imaxpct=25
       =                       sunit=0      swidth=0 blks
  naming   =version 2              bsize=4096   ascii-ci=0 ftype=1
  log      =internal               bsize=4096   blocks=6400, version=2
       =                       sectsz=512   sunit=0 blks, lazy-count=1
  realtime =none                   extsz=4096   blocks=0, rtextents=0
  data blocks changed from 13107200 to 68171776

• 查看最终结果可见root分区容量已经增加

  [root@home www]# fdisk -l
  WARNING: fdisk GPT support is currently new, and therefore in an experimental phase. Use at your own discretion.
  磁盘 /dev/sda：512.1 GB, 512110190592 字节，1000215216 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
  磁盘标签类型：gpt
  Disk identifier: 63761B35-8ECB-411B-8DB1-E51648ECF46C
  \#         Start          End    Size  Type            Name
  1         2048       411647    200M  EFI System      EFI System Partition
  2       411648      2508799      1G  Microsoft basic 
  3      2508800   1000214527  475.8G  Linux LVM       
  磁盘 /dev/mapper/centos_home-root：279.2 GB, 279231594496 字节，545374208 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/mapper/centos_home-swap：16.8 GB, 16844324864 字节，32899072 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/mapper/centos_home-home：214.7 GB, 214748364800 字节，419430400 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

格式化home分区

mkfs.xfs /dev/mapper/centos_home-home -f

重新挂载

mount /dev/mapper/centos_home-home /home

参考文档

https://blog.csdn.net/qq_28808697/article/details/103988967
https://www.cnblogs.com/kevingrace/p/5825963.html