物理服务器后台安装系统前可以自定义分区，没有数据的建议直接重装时分区

举例把/home删除，剩余空间扩容到/

生产中的服务器操作有风险，请谨慎操作，本教程不对任何数据丢失负责

[root@localhost~]#df-h#查看分区情况，准备卸载/home和删除/home所在的lv
FilesystemSizeUsedAvailUse%Mountedon
/dev/mapper/centos-root50G3.8G47G8%/
devtmpfs1.9G01.9G0%/dev
tmpfs1.9G01.9G0%/dev/shm
tmpfs1.9G18M1.9G1%/run
tmpfs1.9G01.9G0%/sys/fs/cgroup
/dev/sda11014M178M837M18%/boot
/dev/mapper/centos-home245G33M245G1%/home
tmpfs379M0379M0%/run/user/0
[root@localhost~]#fdisk-l#查看磁盘lv名称

Disk/dev/sda:322.1GB,322122547200bytes,629145600sectors
Units=sectorsof1*512=512bytes
Sectorsize(logical/physical):512bytes/4096bytes
I/Osize(minimum/optimal):4096bytes/4096bytes
Disklabeltype:dos
Diskidentifier:0x000ed6dc

DeviceBootStartEndBlocksIdSystem
/dev/sda1*20482099199104857683Linux
/dev/sda220992006291455993135232008eLinuxLVM

Disk/dev/mapper/centos-root:53.7GB,53687091200bytes,104857600sectors
Units=sectorsof1*512=512bytes
Sectorsize(logical/physical):512bytes/4096bytes
I/Osize(minimum/optimal):4096bytes/4096bytes


Disk/dev/mapper/centos-swap:4160MB,4160749568bytes,8126464sectors
Units=sectorsof1*512=512bytes
Sectorsize(logical/physical):512bytes/4096bytes
I/Osize(minimum/optimal):4096bytes/4096bytes


Disk/dev/mapper/centos-home:263.2GB,263192576000bytes,514048000sectors
Units=sectorsof1*512=512bytes
Sectorsize(logical/physical):512bytes/4096bytes
I/Osize(minimum/optimal):4096bytes/4096bytes

[root@localhost~]#umount/home#卸载/home
[root@localhost~]#lvremove/dev/mapper/centos-home#删除/home所在lv
Doyoureallywanttoremoveactivelogicalvolumecentos/home?[y/n]:y#输入y回车
Logicalvolume"home"successfullyremoved
[root@localhost~]#lvextend-r-l+100%FREE/dev/mapper/centos-root#剩余容量全部分到/，回车后操作完成
Sizeoflogicalvolumecentos/rootchangedfrom50.00GiB(12800extents)to295.12GiB(75551extents).
Logicalvolumecentos/rootsuccessfullyresized.
meta-data=/dev/mapper/centos-rootisize=512agcount=4,agsize=3276800blks
=sectsz=4096attr=2,projid32bit=1
=crc=1finobt=0spinodes=0
data=bsize=4096blocks=13107200,imaxpct=25
=sunit=0swidth=0blks
naming=version2bsize=4096ascii-ci=0ftype=1
log=internalbsize=4096blocks=6400,version=2
=sectsz=4096sunit=1blks,lazy-count=1
realtime=noneextsz=4096blocks=0,rtextents=0
datablockschangedfrom13107200to77364224
[root@localhost~]#df-h#根目录现在已经扩容完成
FilesystemSizeUsedAvailUse%Mountedon
/dev/mapper/centos-root296G3.8G292G2%/
devtmpfs1.9G01.9G0%/dev
tmpfs1.9G01.9G0%/dev/shm
tmpfs1.9G18M1.9G1%/run
tmpfs1.9G01.9G0%/sys/fs/cgroup
/dev/sda11014M178M837M18%/boot
tmpfs379M0379M0%/run/user/0
[root@localhost~]#vi/etc/fstab#需要编辑此文件，删除/home分区挂载，不然重启后会无法开机

#/etc/fstab
#CreatedbyanacondaonSatMar706:19:072020
#
#Accessiblefilesystems,byreference,aremaintainedunder'/dev/disk'
#Seemanpagesfstab(5),findfs(8),mount(8)and/orblkid(8)formoreinfo
#
/dev/mapper/centos-root/xfsdefaults00
UUID=c02c8818-6a16-49df-a6f2-89e377303b9c/bootxfsdefaults00
/dev/mapper/centos-home/homexfsdefaults00#删除这一行保存退出
/dev/mapper/centos-swapswapswapdefaults00