我们做服务器搭建维护的时候都会因为各种需求而需要调整分区大小。为了效率我们肯定要做到无损的调整，而可能很多不是很熟练的人不知道怎么调，下面小编就为大家分享下linux服务器无损调整分区大小的'方法吧。
情况：
home：500G
root：50G
root分区不够用
思路：把home分区的空间划一部分到root分区
# 设置home分区大小为200G，释放300G空间
$ lvreduce -L 200G /dev/centos/home
# 将空闲空间扩展到root分区
$ lvextend -l +100%FREE /dev/centos/root
# 使用XFS文件系统自带的命令集增加分区空间
$ xfs_growfs /dev/mapper/centos-root
实例
situation
挂载在根目录的分区 /dev/mapper/centos-root 爆满，占用100%
$ df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/centos-root 50G 50G 19M 100% /
devtmpfs 32G 0 32G 0% /dev
tmpfs 32G 0 32G 0% /dev/shm
tmpfs 32G 2.5G 29G 8% /run
tmpfs 32G 0 32G 0% /sys/fs/cgroup
/dev/mapper/centos-home 476G 33M 476G 1% /home
/dev/sda1 497M 238M 259M 48% /boot
tmpfs 6.3G 0 6.3G 0% /run/user/0
analyze
挂载在根目录的分区空间太小，只有50G，而服务器 home 目录为非常用目录，挂在了近500G的空间。
思路：从 centos-home 分区划出300G空间到 centos-root 分区。
operation
1.查看各分区信息
$ lvdisplay
--- Logical volume ---
LV Path /dev/centos/home
LV Name home
VG Name centos
LV UUID 1fAt1E-bQsa-1HXR-MCE2-5VZ1-xzBz-iI1SLv
LV Write Access read/write
LV Creation host, time localhost, 2016-10-26 17:23:47 +0800
LV Status available
# open 0
LV Size 475.70 GiB
Current LE 121778
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 253:2
--- Logical volume ---
LV Path /dev/centos/root
LV Name root
VG Name centos
LV UUID lD64zY-yc3Z-SZaB-dAjK-03YM-2gM8-pfj4oo
LV Write Access read/write
LV Creation host, time localhost, 2016-10-26 17:23:48 +0800
LV Status available
# open 1
LV Size 50.00 GiB
Current LE 12800
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 253:0
2.减少/home分区空间
# 释放 /dev/centos/home 分区 300G 的空间
# 命令设置 /dev/centos/home 分区 200G空间
$ lvreduce -L 200G /dev/centos/home
WARNING: Reducing active logical volume to 200.00 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 475.70 GiB (121778 extents) to 200.00 GiB (51200 extents).
Logical volume centos/home successfully resized.
3.增加/root分区空间
$ lvextend -l +100%FREE /dev/centos/root
Size of logical volume centos/root changed from 50.06 GiB (12816 extents) to 325.76 GiB (83394 extents).
Logical volume centos/root successfully resized.
4.扩展XFS文件空间大小
$ xfs_growfs /dev/mapper/centos-root
meta-data=/dev/mapper/centos-root isize=256 agcount=4, agsize=3276800 blks
= sectsz=512 attr=2, projid32bit=1
= crc=0 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=0
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 85395456
