CentOS7上lvm分区调整（resize2fs: Bad magic number in super-block while trying to open ...）

问题描述：根目录空间占用率100%

首先用传统resize2fs方式调整分区：

resize2fs -p /dev/mapper/centos-home 50G
resize2fs 1.42.9 (28-Dec-2013)
resize2fs: Bad magic number in super-block while trying to open /dev/mapper/centos-home
Couldn't find valid filesystem superblock.

报错原因是因为文件系统是xfs（fdisk -l查看），不再支持resize2fs

解决思路：

①确认分区类型为lvm

②查看到home分区有大量闲置空间，决定将home的空间分配给 /

卸载home  >>  删除home  >>  将home的空间添加到 " / "   >>   重新分配home  >>   格式化home  >> 完成

会用到的命令：

df -h　　　　　　   # 查看磁盘空间

lsblk　　　　　　　# 查看块设备详情

fdisk -l                      # 查看分区详情

lvremove\lvcreate    # 逻辑卷删除/创建

lvdisplay\vgdisplay\pvdisplay   #查看逻辑卷/卷组/物理卷

xfs_growfs               # 加载xfs_growfs

操作过程：

1、分析：查看分区详情，看到sda2为lvm逻辑卷，所以可以通过将home的空间转移到根分区

# lsblk
NAME            MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
fd0               :         4K   disk
sda               :       300G   disk
├─sda1            :       500M   part /boot
└─sda2            :     .5G   part
  ├─centos-root :        50G   lvm  /
  ├─centos-swap :       .8G   lvm  [SWAP]
  └─centos-home :     .6G   lvm  /home
sr0              :      1024M   rom

2、/home备份

# mkdir /tmp/home
# cp -r /home/* /tmp/home

3、umount卸载

# umount /home
umount: /home: target is busy.
        (In some cases useful info about processes that use
         the device is found by lsof() or fuser())

# 如果提示busy，则使用fuser解除占用
# fuser -m -v -i -k /home

4、删除home逻辑卷（lv），将home的空间腾出来到卷组（vg）

# lvremove /dev/mapper/centos-home
Do you really want to remove active logical volume home? [y/n]: y
  Logical volume "home" successfully removed

5、重新调整 / 的大小

# lvextend -L 250G /dev/mapper/centos-root  # 调整到250G
  Size of logical volume centos/root changed from 50.00 GiB ( extents) to 250.00 GiB ( extents).
  Logical volume root successfully resized.

xfs_growfs刷新

# xfs_growfs /dev/mapper/centos-root
meta-data=/dev/mapper/centos-root isize=    agcount=, agsize= blks
         =                       sectsz=  attr=, projid32bit=
         =                       crc=        finobt=
data     =                       bsize=   blocks=, imaxpct=
         =                       sunit=      swidth= blks
naming   =version               bsize=   ascii-ci= ftype=
log      =internal               bsize=   blocks=, version=
         =                       sectsz=  sunit= blks, lazy-count=
realtime =none                   extsz=   blocks=, rtextents=
data blocks changed from  to 

6、将剩下的空间重新划分到home中

# lvcreate -l +%free -n home centos         # -n 指定lv的名字，centos是vg的名字
  Logical volume "home" created.

创建完成别忘了格式化

# mkfs.xfs /dev/centos/home
meta-data=/dev/centos/home       isize=    agcount=, agsize= blks
         =                       sectsz=  attr=, projid32bit=
         =                       crc=        finobt=
data     =                       bsize=   blocks=, imaxpct=
         =                       sunit=      swidth= blks
naming   =version               bsize=   ascii-ci= ftype=
log      =internal log           bsize=   blocks=, version=
         =                       sectsz=  sunit= blks, lazy-count=
realtime =none                   extsz=   blocks=, rtextents=

7、重新mount并查看

# mount /dev/mapper/centos-home /home

8、完成

9、别忘了把home备份还原