Centos缩容home磁盘空间到根目录/下操作
背景
自己在家里老笔记搭建的CentOS7系统用来跑一些服务，前段时间通过samba共享存储把小米摄像头视频进行实时转存到笔记本上，最近发现磁盘不足了，因为我默认是挂载到根目录下的，以前安装操作系统时把所有空间分配给了/home目录下，现在根目录的磁盘空间，又不想更改目录，所以打算把/home目录的空间腾出挂载给根目录，于是有了本篇文章。
准备工作
查看当前磁盘分配：
[root@lcrycentos7 ~]# df -hT
Filesystem Type Size Used Avail Use% Mounted on
devtmpfs devtmpfs 1.7G 0 1.7G 0% /dev
tmpfs tmpfs 1.7G 0 1.7G 0% /dev/shm
tmpfs tmpfs 1.7G 170M 1.6G 10% /run
tmpfs tmpfs 1.7G 0 1.7G 0% /sys/fs/cgroup
/dev/mapper/centos_centos7-root xfs 50G 28G 23G 55% /
/dev/sda1 xfs 1014M 311M 704M 31% /boot
/dev/mapper/centos_centos7-home xfs 411G 33M 411G 1% /home
overlay overlay 50G 28G 23G 55% /var/lib/docker/overlay2/0e259cb791ddad0681ebfd184c6408ed5078d362c54b9a9a0815c6edc1f98cf7/merged
tmpfs tmpfs 347M 0 347M 0% /run/user/0- 确认 /home 挂载点的文件系统路径
/dev/mapper/centos_centos7-home所对应的卷组 centos 和逻辑卷 home - 确认 / 挂载点的文件系统路径
/dev/mapper/centos_centos7-root所对应的卷组 centos 和逻辑卷 root - Centos系统默认是xfs文件系统，且xfs文件系统只能扩容不能缩减，在必须缩减逻辑卷容量的前提下，需要使用
xfsdump/xfsrestore进行备份和还原
扩缩容操作
备份 /home 挂载点内容
## 若没有先安装工具 [root@lcrycentos7 ~]# yum -y install xfsdump [root@lcrycentos7 ~]# xfsdump -f /home.xfsdump /home xfsdump: using file dump (drive_simple) strategy xfsdump: version 3.1.7 (dump format 3.0) - type ^C for status and control ============================= dump label dialog ============================== please enter label for this dump session (timeout in 300 sec) -> home session label entered: "home" --------------------------------- end dialog --------------------------------- xfsdump: level 0 dump of lcrycentos7:/home xfsdump: dump date: Sat Apr 16 10:44:14 2022 xfsdump: session id: 44b0f62a-7a5d-40bd-aecb-23b588e7d01f xfsdump: session label: "home" xfsdump: ino map phase 1: constructing initial dump list xfsdump: ino map phase 2: skipping (no pruning necessary) xfsdump: ino map phase 3: skipping (only one dump stream) xfsdump: ino map construction complete xfsdump: estimated dump size: 20800 bytes xfsdump: /var/lib/xfsdump/inventory created ============================= media label dialog ============================= please enter label for media in drive 0 (timeout in 300 sec) -> home media label entered: "home" --------------------------------- end dialog --------------------------------- xfsdump: creating dump session media file 0 (media 0, file 0) xfsdump: dumping ino map xfsdump: dumping directories xfsdump: dumping non-directory files xfsdump: ending media file xfsdump: media file size 21352 bytes xfsdump: dump size (non-dir files) : 0 bytes xfsdump: dump complete: 11 seconds elapsed xfsdump: Dump Summary: xfsdump: stream 0 /home.xfsdump OK (success) xfsdump: Dump Status: SUCCESS成功备份后，卸载 /home 挂载点
[root@lcrycentos7 ~]# umount /home减少 /home 挂载点对应的逻辑卷大小
[root@lcrycentos7 ~]# lvreduce -L 80G /dev/mapper/centos_centos7-home WARNING: Reducing active logical volume to 80.00 GiB. THIS MAY DESTROY YOUR DATA (filesystem etc.) Do you really want to reduce centos_centos7/home? [y/n]: y Size of logical volume centos_centos7/home changed from <411.13 GiB (105249 extents) to 80.00 GiB (20480 extents). Logical volume centos_centos7/home successfully resized.增加 / 挂载点对应的逻辑卷大小（将卷组中的空闲空间全部扩展到根分区逻辑卷）
[root@lcrycentos7 ~]# lvextend -l +100%FREE /dev/mapper/centos_centos7-root Size of logical volume centos_centos7/root changed from 50.00 GiB (12800 extents) to 381.13 GiB (97570 extents). Logical volume centos_centos7/root successfully resized.注：这个是分配所有可用空间给根目录，也可以使用
lvextend -r -L 200G /dev/mapper/centos_centos7-root命令指定大小。
-L：指定逻辑卷的大小，单位为“kKmMgGtT”字节；
-l：指定逻辑卷的大小（LE数）。执行扩容生效
[root@lcrycentos7 ~]# xfs_growfs /dev/mapper/centos_centos7-root meta-data=/dev/mapper/centos_centos7-root isize=512 agcount=4, agsize=3276800 blks = sectsz=4096 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=4096 sunit=1 blks, lazy-count=1 realtime =none extsz=4096 blocks=0, rtextents=0 data blocks changed from 13107200 to 99911680格式化 /home 挂载点对应的逻辑卷
[root@lcrycentos7 ~]# mkfs.xfs -f /dev/mapper/centos_centos7-home meta-data=/dev/mapper/centos_centos7-home isize=512 agcount=4, agsize=5242880 blks = sectsz=4096 attr=2, projid32bit=1 = crc=1 finobt=0, sparse=0 data = bsize=4096 blocks=20971520, imaxpct=25 = sunit=0 swidth=0 blks naming =version 2 bsize=4096 ascii-ci=0 ftype=1 log =internal log bsize=4096 blocks=10240, version=2 = sectsz=4096 sunit=1 blks, lazy-count=1 realtime =none extsz=4096 blocks=0, rtextents=0重新挂载 /home
[root@lcrycentos7 ~]# mount /home恢复备份内容到 /home 挂载点
[root@lcrycentos7 ~]# xfsrestore -f /home.xfsdump /home xfsrestore: using file dump (drive_simple) strategy xfsrestore: version 3.1.7 (dump format 3.0) - type ^C for status and control xfsrestore: searching media for dump xfsrestore: examining media file 0 xfsrestore: dump description: xfsrestore: hostname: lcrycentos7 xfsrestore: mount point: /home xfsrestore: volume: /dev/mapper/centos_centos7-home xfsrestore: session time: Sat Apr 16 10:44:14 2022 xfsrestore: level: 0 xfsrestore: session label: "home" xfsrestore: media label: "home" xfsrestore: file system id: af18ea4a-cd62-4d8f-a1ac-752b805e20db xfsrestore: session id: 44b0f62a-7a5d-40bd-aecb-23b588e7d01f xfsrestore: media id: 9cf7c8b3-b948-4535-8750-097a66ccd991 xfsrestore: using online session inventory xfsrestore: searching media for directory dump xfsrestore: reading directories xfsrestore: 1 directories and 0 entries processed xfsrestore: directory post-processing xfsrestore: restore complete: 0 seconds elapsed xfsrestore: Restore Summary: xfsrestore: stream 0 /home.xfsdump OK (success) xfsrestore: Restore Status: SUCCESS检查扩容是否升级
[root@lcrycentos7 ~]# df -hT Filesystem Type Size Used Avail Use% Mounted on devtmpfs devtmpfs 1.7G 0 1.7G 0% /dev tmpfs tmpfs 1.7G 0 1.7G 0% /dev/shm tmpfs tmpfs 1.7G 170M 1.6G 10% /run tmpfs tmpfs 1.7G 0 1.7G 0% /sys/fs/cgroup /dev/mapper/centos_centos7-root xfs 382G 28G 354G 8% / /dev/sda1 xfs 1014M 311M 704M 31% /boot overlay overlay 382G 28G 354G 8% /var/lib/docker/overlay2/0e259cb791ddad0681ebfd184c6408ed5078d362c54b9a9a0815c6edc1f98cf7/merged tmpfs tmpfs 347M 0 347M 0% /run/user/0 /dev/mapper/centos_centos7-home xfs 80G 33M 80G 1% /home- 最后为了保险起见重启服务器再检查一遍
参考
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