linux如何无损调整分区大小扩容磁盘的详细教程方法
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
完成
