linux系统下对目录扩容

1、现象：日志服务器当初考虑不周，分区划分不太合理：

2、目标：将/home磁盘空间缩减 并将新的磁盘分区扩充到/根目录

卸载/home分区并压缩分区

卸载/home时 提示目标忙，fuser -m /home查看谁用/home时提示没有fuser命令
[root@localhost zabbix]# umount /home
umount: /home：目标忙。

    (有些情况下通过 lsof(8) 或 fuser(1) 可以
     找到有关使用该设备的进程的有用信息)

[root@localhost zabbix]# fuser -m /home
-bash: fuser: 未找到命令
解决没有fuser命令的问题：
在CentOS / RHEL 7上找不到fuser命令

-bash: fuser: command not found
yum install psmisc

fuser -m /home //继续查找谁在用/home

kill -9 11757 //停止进程
umount /home //卸载/home文件系统

压缩分区：resize2fs -p /dev/mapper/centos-home 100G

确认是xfs格式系统

cat /etc/fstab|grep centos-home

xfs文件系统扩容必须安装 xfsdump工具
yum install xfsdump -y

减少/home空间到100GB：

lvreduce -L 100G /dev/mapper/centos-home
[root@localhost ~]# lvreduce -L 100G /dev/mapper/centos-home
WARNING: Reducing active logical volume to 100.00 GiB
THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce home? [y/n]: y
Reducing logical volume home to 100.00 GiB
Logical volume home successfully resized
[root@localhost ~]#

增大根目录

lvextend -l +100%FREE /dev/mapper/centos-root
[root@localhost ~]# lvextend -l +100%FREE /dev/mapper/centos-root
Extending logical volume root to 167.37 GiB
Logical volume root successfully resized

延伸/目录空间

xfs_growfs /dev/mapper/centos-root
[root@localhost ~]# 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

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 43874304
[root@localhost ~]#

重新挂载/home

[root@localhost ~]# mount /home
mount: /dev/mapper/centos-home：不能读超级块

必须格式化/home分区，才能挂载----所以缩减/home分区之前必须备份/home的内容（切记！！！）
mkfs.xfs -f /dev/mapper/centos-home
[root@localhost ~]# mkfs.xfs -f /dev/mapper/centos-home
meta-data=/dev/mapper/centos-home isize=256 agcount=4, agsize=6553600 blks

     =                       sectsz=512   attr=2, projid32bit=1
     =                       crc=0

data = bsize=4096 blocks=26214400, imaxpct=25

     =                       sunit=0      swidth=0 blks

naming =version 2 bsize=4096 ascii-ci=0 ftype=0
log =internal log bsize=4096 blocks=12800, version=2

     =                       sectsz=512   sunit=0 blks, lazy-count=1

realtime =none extsz=4096 blocks=0, rtextents=0

重新挂载mount /home