1、現象：日誌伺服器當初考慮不周，分區劃分不太合理：

2、目標：將/home磁碟空間縮減 並將新的磁碟分割槽擴充到/根目錄

解除安裝/home分割槽並壓縮分割槽

解除安裝/home時 提示目標忙，fuser -m /home檢視誰用/home時提示沒有fuser命令

[root@localhost zabbix]# umount /home
umount: /home：目標忙。
        (有些情況下通過 lsof(8) 或 fuser(1) 可以
         找到有關使用該裝置的程序的有用資訊)
[root@localhost zabbix]# fuser -m /home
-bash: fuser
 
: 未找到命令
解決沒有fuser命令的問題：
在CentOS / RHEL 7上找不到fuser命令
-bash: fuser: command not found 
yum install psmisc 

fuser -m /home //繼續查詢誰在用/home

kill -9 11757 //停止程序
umount /home //解除安裝/home檔案系統

壓縮分割槽：resize2fs -p /dev/mapper/centos-home 100G

確認是xfs格式系統

cat /etc/fstab|grep centos-home

xfs檔案系統擴容必須安裝 xfsdump工具
 yum install xfsdump -y
減少
 
/home空間到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 
 
~]#

增大根目錄

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/目錄空間

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 ~]#

重新掛載/home

[root@localhost ~]# mount /home
mount: /dev/mapper/centos-home：不能讀超級塊

必須格式化/home分割槽，才能掛載----所以縮減/home分割槽之前必須備份/home的內容（切記！！！）

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

重新掛載mount /home