安裝Linux時全部走的默認(rèn)，導(dǎo)致home路徑過大，由于安裝CDH對home沒有要求，現(xiàn)將home減小，增大根目錄的大小，步驟如下：
1.查看分區(qū)空間和格式
df -h
文件系統(tǒng) 類型 容量 已用 可用 已用% 掛載點
devtmpfs devtmpfs 16G 0 16G 0% /dev
tmpfs tmpfs 16G 0 16G 0% /dev/shm
tmpfs tmpfs 16G 9.7M 16G 1% /run
tmpfs tmpfs 16G 0 16G 0% /sys/fs/cgroup
/dev/mapper/centos-root xfs 50G 6.4G 44G 13% /
/dev/vda2 xfs 1014M 157M 858M 16% /boot
/dev/vda1 vfat 200M 12M 189M 6% /boot/efi
/dev/mapper/centos-home xfs 133G 33M 133G 1% /home
tmpfs tmpfs 3.2G 8.0K 3.2G 1% /run/user/42
tmpfs tmpfs 3.2G 0 3.2G 0% /run/user/0
由此可以看到根目錄與home目錄都是xfs格式，由于xfs文件系統(tǒng)只支持增大分區(qū)空間的情況，不支持減小的情況。
若減小，只能在減小后將邏輯分區(qū)重新通過 mkfs.xfs 命令重新格式化才能掛載上，這樣的話這個邏輯分區(qū)上原來的數(shù)據(jù)就丟失了。
2.卸載/home分區(qū)
umount /home
3.查看分區(qū)情況
df -h
文件系統(tǒng) 類型 容量 已用 可用 已用% 掛載點
devtmpfs devtmpfs 16G 0 16G 0% /dev
tmpfs tmpfs 16G 0 16G 0% /dev/shm
tmpfs tmpfs 16G 9.7M 16G 1% /run
tmpfs tmpfs 16G 0 16G 0% /sys/fs/cgroup
/dev/mapper/centos-root xfs 50G 6.4G 44G 13% /
/dev/vda2 xfs 1014M 157M 858M 16% /boot
/dev/vda1 vfat 200M 12M 189M 6% /boot/efi
tmpfs tmpfs 3.2G 8.0K 3.2G 1% /run/user/42
tmpfs tmpfs 3.2G 0 3.2G 0% /run/user/0
由此可見，/home目錄已經(jīng)被umount掉。
4.將/home對應(yīng)的/dev/mapper/centos-home分區(qū)減小
lvreduce -L -100G /dev/mapper/centos-home
WARNING: Reducing active logical volume to <33.05 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 <133.05 GiB (34060 extents) to <33.05 GiB (8460 extents).
Logical volume centos/home successfully resized.
5.xfs文件系統(tǒng)減小空間需要進行格式化操作
mkfs.xfs /dev/mapper/centos-home -f
meta-data=/dev/mapper/centos-home isize=512 agcount=4, agsize=2165760 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=0, sparse=0
data = bsize=4096 blocks=8663040, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
log =internal log bsize=4096 blocks=4230, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
6.重新掛載/home分區(qū)
mount /dev/mapper/centos-home /home/
7.驗證掛在是否成功
df -h
文件系統(tǒng) 容量 已用 可用 已用% 掛載點
devtmpfs 16G 0 16G 0% /dev
tmpfs 16G 0 16G 0% /dev/shm
tmpfs 16G 9.7M 16G 1% /run
tmpfs 16G 0 16G 0% /sys/fs/cgroup
/dev/mapper/centos-root 50G 6.4G 44G 13% /
/dev/vda2 1014M 157M 858M 16% /boot
/dev/vda1 200M 12M 189M 6% /boot/efi
tmpfs 3.2G 12K 3.2G 1% /run/user/42
tmpfs 3.2G 0 3.2G 0% /run/user/0
/dev/mapper/centos-home 34G 33M 33G 1% /home
8.將釋放了100G空間加到根目錄下
lvextend -L +100G /dev/mapper/centos-root
Size of logical volume centos/root changed from 50.00 GiB (12800 extents) to 150.00 GiB (38400 extents).
Logical volume centos/root successfully resized.
9.添加完成對根目錄分區(qū)進行格式化
xfs_growfs /dev/mapper/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 39321600
10.驗證添加是否成功
df -h
文件系統(tǒng) 容量 已用 可用 已用% 掛載點
devtmpfs 16G 0 16G 0% /dev
tmpfs 16G 0 16G 0% /dev/shm
tmpfs 16G 9.7M 16G 1% /run
tmpfs 16G 0 16G 0% /sys/fs/cgroup
/dev/mapper/centos-root 150G 6.4G 144G 5% /
/dev/vda2 1014M 157M 858M 16% /boot
/dev/vda1 200M 12M 189M 6% /boot/efi
tmpfs 3.2G 12K 3.2G 1% /run/user/42
tmpfs 3.2G 0 3.2G 0% /run/user/0
/dev/mapper/centos-home 34G 33M 33G 1% /home
由此可見，home減少了100G空間，根目錄增加了100G空間。
