查看当前分区情况# df -hT 查看目前的分区情况Filesystem Type Size Used Avail Use% Mounted on安装centos时，采取了默认的分区方案。从上面可以看出硬盘总100G，lv_root 50G ,lv_home 47G
卸载/home# umount /home/# df -hTFilesystem Type Size Used Avail Use% Mounted on从上面看出home分区已经卸载
调整分区大小# resize2fs -p /dev/mapper/vg_test-lv_home 20Gresize2fs 1.41.12 (17-May-2010)Please run 'e2fsck -f /dev/mapper/vg_test-lv_home' first.根据提示执行e2fsck -f /dev/mapper/vg_test-lv_home命令# resize2fs -p /dev/mapper/vg_test-lv_home 20G 将home分区调整到20Gresize2fs 1.41.12 (17-May-2010)# mount /home/ 挂载home# df -hTFilesystem Type Size Used Avail Use% Mounted on看到home已经调整到20G# lvdisplay 查看逻辑卷信息--- Logical volume ---# lvreduce -L 20G /dev/mapper/vg_test-lv_home 减少逻辑卷大小到20GWARNING: Reducing active and open logical volume to 20.00 GiB.# vgdisplay 查看vg信息--- Volume group ---从上面看出有27.57G空闲把闲置空间扩展到根目录# lvextend -L +27.57G /dev/mapper/vg_test-lv_rootRounding size to boundary between physical extents: 27.57 GiB.Size of logical volume vg_test/lv_root changed from 50.00 GiB (12800 extents) to 77.57 GiB (19858 extents).Logical volume lv_root successfully resized.# lvdisplay--- Logical volume ---# resize2fs -p /dev/mapper/vg_test-lv_rootresize2fs 1.41.12 (17-May-2010)Filesystem at /dev/mapper/vg_test-lv_root is mounted on /; on-line resizing requiredold desc_blocks = 4, new_desc_blocks = 5Performing an on-line resize of /dev/mapper/vg_test-lv_root to 20334592 (4k) blocks.The filesystem on /dev/mapper/vg_test-lv_root is now 20334592 blocks long.# df -hTFilesystem Type Size Used Avail Use% Mounted on从上面看到根分区大小已经增加。删除home 逻辑卷并把大小扩展到根目录注意：一定要备份好/home分区下数据查看目前的分区挂载情况# cat /etc/fstab## /etc/fstab# Created by anaconda on Thu Aug 4 11:30:04 2016## Accessible filesystems, by reference, are maintained under '/dev/disk'# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info#/dev/mapper/vg_test-lv_root / ext4 defaults 1 1UUID=adbd2476-a3f6-4fa1-b94c-0ec859e22195 /boot ext4 defaults 1 2/dev/mapper/vg_test-lv_home /home ext4 defaults 1 2/dev/mapper/vg_test-lv_swap swap swap defaults 0 0tmpfs /dev/shm tmpfs defaults 0 0devpts /dev/pts devpts gid=5,mode=620 0 0sysfs /sys sysfs defaults 0 0proc /proc proc defaults 0 0# umount /dev/mapper/vg_test-lv_home 卸载home逻辑卷# lvremove /dev/mapper/vg_test-lv_home 删除逻辑卷Do you really want to remove active logical volume lv_home? [y/n]: yLogical volume 'lv_home' successfully removed# lvdisplay--- Logical volume ---从上面看出逻辑卷home已经删除将空闲空间扩展到跟分区# vgdisplay--- Volume group ---从上面看出空闲20G，正好是删除的home逻辑卷大小# lvextend -L +20G /dev/mapper/vg_test-lv_rootSize of logical volume vg_test/lv_root changed from 77.57 GiB (19858 extents) to 97.57 GiB (24978 extents).Logical volume lv_root successfully resized.# lvdisplay--- Logical volume ---看到根目录已经扩展# resize2fs /dev/mapper/vg_test-lv_rootresize2fs 1.41.12 (17-May-2010)Filesystem at /dev/mapper/vg_test-lv_root is mounted on /; on-line resizing requiredold desc_blocks = 5, new_desc_blocks = 7Performing an on-line resize of /dev/mapper/vg_test-lv_root to 25577472 (4k) blocks.The filesystem on /dev/mapper/vg_test-lv_root is now 25577472 blocks long.# df -hTFilesystem Type Size Used Avail Use% Mounted on# cat /etc/fstab#如果忘记修改fstab，重启后，根据提示输入密码# mount / -o remount然后在修改fstab