1.查看root和home下的容量
[root@localhost ~]# df -hFilesystem Size Used Avail Use% Mounted on/dev/mapper/cl-root 50G 952M 50G 2% /devtmpfs 63G0 63G 0% /devtmpfs 63G0 63G 0% /dev/shmtmpfs 63G 9.1M 63G 1% /runtmpfs 63G0 63G 0% /sys/fs/cgroup/dev/sda2 1014M 139M 876M 14% /boot/dev/mapper/cl-home 5.3T 33M 5.3T 1% /hometmpfs 13G0 13G 0% /run/user/0
home下面有5.3T的容量，root下面的容量只有50G
2.先将home下面的所有文件备份到/tmp下，一会要重新分配home，不备份数据将会丢失
[root@localhost home]# tar cvfP /tmp/home.tar /home/home/
tar命令后面不加P，会报错tar: Removing leading `/' from member names，原因是tar默认是相对路径，用绝对路径会报错，加上P就可以了。
3.将/home目录卸载掉
[root@localhost home]# umount -v /homeumount: /home: target is busy.(In some cases useful info about processes that usethe device is found by lsof(8) or fuser(1))
竟然报错，home正忙，根据提示用fuser命令
[root@localhost home]# fuser -km /home/-bash: fuser: command not found
新机器这个命令没有安装，装一下
[root@localhost home]# yum install -y psmiscResolving Dependencies--> Running transaction check---> Package psmisc.x86_64 0:22.20-16.el7 will be installed--> Finished Dependency ResolutionDependencies Resolved============================================================================================================================================PackageArch Version Repository Size============================================================================================================================================Installing:psmiscx86_6422.20-16.el7 base141 kTransaction Summary============================================================================================================================================Install 1 PackageTotal download size: 141 kInstalled size: 475 kDownloading packages:warning: /var/cache/yum/x86_64/7/base/packages/psmisc-22.20-16.el7.x86_64.rpm: Header V3 RSA/SHA256 Signature, key ID f4a80eb5: NOKEY-- ETA Public key for psmisc-22.20-16.el7.x86_64.rpm is not installedpsmisc-22.20-16.el7.x86_64.rpm | 141 kB 00:00:02Retrieving key from file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7Importing GPG key 0xF4A80EB5:Userid: "CentOS-7 Key (CentOS 7 Official Signing Key) <security@>"Fingerprint: 6341 ab27 53d7 8a78 a7c2 7bb1 24c6 a8a7 f4a8 0eb5Package : centos-release-7-3.1611.el7.centos.x86_64 (@anaconda)From : /etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7Running transaction checkRunning transaction testTransaction test succeededRunning transactionInstalling : psmisc-22.20-16.el7.x86_641/1 Verifying : psmisc-22.20-16.el7.x86_641/1 Installed:psmisc.x86_64 0:22.20-16.el7Complete!
装好了，再重复fuser -km /home/和umount -v /home即可
4.删除/home的lv
[root@localhost ~]# lvremove /dev/mapper/cl-homeDo you really want to remove active logical volume cl/home? [y/n]: yLogical volume "home" successfully removed
5.把home中的5T拿来给root
[root@localhost ~]# lvextend -L +5T /dev/mapper/cl-rootSize of logical volume cl/root changed from 50.00 GiB (12800 extents) to 5.05 TiB (1323520 extents).Logical volume cl/root successfully resized.
6.扩展root文件系统
[root@localhost ~]# xfs_growfs /dev/mapper/cl-rootmeta-data=/dev/mapper/cl-root isize=512 agcount=4, agsize=3276800 blks= sectsz=4096 attr=2, projid32bit=1= crc=1 finobt=0 spinodes=0data= bsize=4096 blocks=13107200, imaxpct=25= sunit=0swidth=0 blksnaming =version 2 bsize=4096 ascii-ci=0 ftype=1log=internalbsize=4096 blocks=6400, version=2= sectsz=4096 sunit=1 blks, lazy-count=1realtime =none extsz=4096 blocks=0, rtextents=0data blocks changed from 13107200 to 1355284480
7.重新创建/home lv.要计算好分配的容量，我这从剩下的分配200G
[root@localhost ~]# lvcreate -L 200G -n /dev/mapper/cl-homeLogical volume "home" created.
8.创建文件系统
[root@localhost ~]# mkfs.xfs /dev/mapper/cl-homemeta-data=/dev/mapper/cl-home isize=512 agcount=4, agsize=13107200 blks= sectsz=4096 attr=2, projid32bit=1= crc=1 finobt=0, sparse=0data= bsize=4096 blocks=52428800, imaxpct=25= sunit=0swidth=0 blksnaming =version 2 bsize=4096 ascii-ci=0 ftype=1log=internal log bsize=4096 blocks=25600, version=2= sectsz=4096 sunit=1 blks, lazy-count=1realtime =none extsz=4096 blocks=0, rtextents=0
9.挂载home
[root@localhost ~]# mount /dev/mapper/cl-home
10.还原备份的/home文件
[root@localhost ~]# tar xvfP /tmp/home.tar -C /home//home/
11.查看分区情况
[root@iiebigdata3 ~]# df -hFilesystem Size Used Avail Use% Mounted on/dev/mapper/cl-root 5.1T 1.1G 5.1T 1% /devtmpfs 63G0 63G 0% /devtmpfs 63G0 63G 0% /dev/shmtmpfs 63G 9.1M 63G 1% /runtmpfs 63G0 63G 0% /sys/fs/cgroup/dev/sda2 1014M 139M 876M 14% /boottmpfs 13G0 13G 0% /run/user/0/dev/mapper/cl-home 200G 33M 200G 1% /home
root变成了5.1T，home变成了200G，成功分配
