由於項目規定程序目錄在根目錄，在安裝系統時沒有及時規划分區，導致根分區空間太小，現決定對根分區進行擴容,准備將home目錄所在的分區進行縮容，將縮容的空間擴容到根分區.
1.查看現有磁盤分區
[root@service1 cloud]# df -Th Filesystem Type Size Ued Avail Use% Mounted on /dev/mapper/centos-root xfs 50G 1006M 49G 2% / devtmpfs devtmpfs 7.8G 0 7.8G 0% /dev tmpfs tmpfs 7.8G 0 7.8G 0% /dev/shm tmpfs tmpfs 7.8G 9.2M 7.8G 1% /run tmpfs tmpfs 7.8G 0 7.8G 0% /sys/fs/cgroup /dev/xvda1 xfs 1014M 145M 870M 15% /boot /dev/mapper/centos-home xfs 42G 33M 42G 1% /home tmpfs tmpfs 1.6G 0 1.6G 0% /run/user/0
2.卸載磁盤home目錄的掛載分區
[root@service1 cloud]# umount /dev/mapper/centos-home
3.將卸載的磁盤分區重新進行格式化成ext4格式.
[root@service1 cloud]# mkfs.ext4 /dev/mapper/centos-home mke2fs 1.42.9 (28-Dec-2013) Filesystem label= OS type: Linux Block size=4096 (log=2) Fragment size=4096 (log=2) Stride=0 blocks, Stripe width=0 blocks 2695168 inodes, 10778624 blocks 538931 blocks (5.00%) reserved for the super user First data block=0 Maximum filesystem blocks=2160066560 329 block groups 32768 blocks per group, 32768 fragments per group 8192 inodes per group Superblock backups stored on blocks: 32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, 4096000, 7962624 Allocating group tables: done Writing inode tables: done Creating journal (32768 blocks): done Writing superblocks and filesystem accounting information: done
4.強制檢查 /dev/mapper/centos-home 是否正常，如果有異常便自動修復
[root@service1 cloud]# e2fsck -f /dev/mapper/centos-home e2fsck 1.42.9 (28-Dec-2013) Pass 1: Checking inodes, blocks, and sizes Pass 2: Checking directory structure Pass 3: Checking directory connectivity Pass 4: Checking reference counts Pass 5: Checking group summary information /dev/mapper/centos-home: 11/2695168 files (0.0% non-contiguous), 214252/10778624 block
5.resize2fs擴展文件系統，將/dev/mapper/centos-home文件系統指定為20G大小.
[root@service1 cloud]# resize2fs /dev/mapper/centos-home 20G resize2fs 1.42.9 (28-Dec-2013) Resizing the filesystem on /dev/mapper/centos-home to 5242880 (4k) blocks. The filesystem on /dev/mapper/centos-home is now 5242880 blocks long.
6.掛載文件系統到home目錄,我們發現為20G.
[root@service1 cloud]# mount /dev/mapper/centos-home /home/ [root@service1 cloud]# df -Th Filesystem Type Size Used Avail Use% Mounted on /dev/mapper/centos-root xfs 50G 1006M 49G 2% / devtmpfs devtmpfs 7.8G 0 7.8G 0% /dev tmpfs tmpfs 7.8G 0 7.8G 0% /dev/shm tmpfs tmpfs 7.8G 9.2M 7.8G 1% /run tmpfs tmpfs 7.8G 0 7.8G 0% /sys/fs/cgroup /dev/xvda1 xfs 1014M 145M 870M 15% /boot tmpfs tmpfs 1.6G 0 1.6G 0% /run/user/0 /dev/mapper/centos-home ext4 20G 45M 19G 1% /home
7.lvreduce縮小邏輯卷,/dev/mapper/centos-home文件系統對應的邏輯卷為/dev/mapper/centos-home，縮小邏輯區22G。
[root@service2 ~]# lvreduce -L 22G /dev/mapper/centos-home WARNING: Reducing active and open logical volume to 22.00 GiB. THIS MAY DESTROY YOUR DATA (filesystem etc.) Do you really want to reduce centos/home? [y/n]: y Size of logical volume centos/home changed from <41.12 GiB (10526 extents) to 22.00 GiB (5632 extents). Logical volume centos/home successfully resized.
8.查看卷組
[root@service1 cloud]# vgs VG #PV #LV #SN Attr VSize VFree centos 1 3 0 wz--n- <99.00g 19.12g
9. lvextend是擴展邏輯卷，將縮小的22G邏輯卷擴展到根目錄分區的邏輯卷中.
[root@service1 cloud]# lvextend -L +19G /dev/mapper/centos-root Size of logical volume centos/root changed from 50.00 GiB (12800 extents) to 69.00 GiB (17664 extents). Logical volume centos/root successfully resized.
10.因為根目錄的文件系統類型為xfs文件類型，使用xfs_growfs同步根分區.
[root@service1 cloud]# xfs_growfs /dev/centos/root meta-data=/dev/mapper/centos-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 18087936 [root@service1 cloud]#
#查看后發現，根分區的目錄以擴展了19G.
#由於home目錄也是xfs文件類型，所以需要將home目錄卸載到重新格式化成xfs，然后再掛載即可.
#格式化為xfs文件系統並重新掛載. mkfs.xfs -f /dev/mapper/centos-home mount /dev/mapper/centos-home /home # [root@service1 cloud]# df -Th Filesystem Type Size Used Avail Use% Mounted on /dev/mapper/centos-root xfs 69G 1006M 68G 2% / devtmpfs devtmpfs 7.8G 0 7.8G 0% /dev tmpfs tmpfs 7.8G 0 7.8G 0% /dev/shm tmpfs tmpfs 7.8G 9.2M 7.8G 1% /run tmpfs tmpfs 7.8G 0 7.8G 0% /sys/fs/cgroup /dev/xvda1 xfs 1014M 145M 870M 15% /boot tmpfs tmpfs 1.6G 0 1.6G 0% /run/user/0 /dev/mapper/centos-home xfs 22G 33M 22G 1% /home [root@service1 cloud]#
參考文檔：https://www.cnblogs.com/happy-king/p/9070496.html