LVM缩小空间操作

根目录今天满盘后导致系统停机, 梳理发现当初分区不合理, 于是想调整/home与/的分配

# df -h
Filesystem               Size  Used Avail Use% Mounted on
devtmpfs                  32G     0   32G   0% /dev
tmpfs                     32G  893M   31G   3% /dev/shm
tmpfs                     32G  8.9M   32G   1% /run
tmpfs                     32G     0   32G   0% /sys/fs/cgroup
/dev/mapper/centos-root   50G   39G   12G  77% /
/dev/sda2               1014M  179M  836M  18% /boot
/dev/sda1                200M   12M  189M   6% /boot/efi
/dev/mapper/centos-home   72G   33M   72G   1% /home
tmpfs                    6.3G     0  6.3G   0% /run/user/11012
tmpfs                    6.3G     0  6.3G   0% /run/user/0

# lvresize -L 10G /dev/mapper/centos-home
  WARNING: Reducing active and open logical volume to 10.00 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 71.92 GiB (18412 extents) to 10.00 GiB (2560 extents).
  Logical volume centos/home successfully resized.
# mount -a
mount: /dev/mapper/centos-home: can't read superblock

这时候发现不对劲

# xfs_repair /dev/mapper/centos-home
Phase 1 - find and verify superblock...
error reading superblock 1 -- seek to offset 19306381312 failed
couldn't verify primary superblock - attempted to perform I/O beyond EOF !!!

attempting to find secondary superblock...
Sorry, could not find valid secondary superblock
Exiting now.

赶紧恢复原样

# lvresize -L 72G /dev/mapper/centos-home
  Size of logical volume centos/home changed from 10.00 GiB (2560 extents) to 72.00 GiB (18432 extents).
  Logical volume centos/home successfully resized.

# xfs_repair /dev/mapper/centos-home
Phase 1 - find and verify superblock...
Phase 2 - using internal log
        - zero log...
ERROR: The filesystem has valuable metadata changes in a log which needs to
be replayed.  Mount the filesystem to replay the log, and unmount it before
re-running xfs_repair.  If you are unable to mount the filesystem, then use
the -L option to destroy the log and attempt a repair.
Note that destroying the log may cause corruption -- please attempt a mount
of the filesystem before doing this.
# mount /dev/mapper/centos-home /home
# ls /home
grid  oracle

这次改用稳妥点的方式

先备份！

# tar cvf /root/home_backup.tar -C /home .

缩小容量并重新格式化

# umount /home

# lvresize -L 10G /dev/mapper/centos-home
  WARNING: Reducing active logical volume to 10.00 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 72.00 GiB (18432 extents) to 10.00 GiB (2560 extents).
  Logical volume centos/home successfully resized.
# mkfs.xfs /dev/mapper/centos-home -f
Discarding blocks...Done.
meta-data=/dev/mapper/centos-home isize=512    agcount=4, agsize=655360 blks
         =                       sectsz=4096  attr=2, projid32bit=1
         =                       crc=1        finobt=0, sparse=0
data     =                       bsize=4096   blocks=2621440, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0 ftype=1
log      =internal log           bsize=4096   blocks=2560, version=2
         =                       sectsz=4096  sunit=1 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0

挂盘与还原数据

# mount /dev/mapper/centos-home /home
# tar xvf /root/home_backup.tar -C /home

检查数据后正常

现在要增加 / 的空间

# lvresize -l +100%FREE /dev/mapper/centos-root
  Size of logical volume centos/root changed from 50.00 GiB (12800 extents) to 234.92 GiB (60140 extents).
  Logical volume centos/root successfully resized.
# xfs_growfs /
meta-data=/dev/mapper/centos-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 61583360

操作成功！

再次检查

# df -h
Filesystem               Size  Used Avail Use% Mounted on
devtmpfs                  32G     0   32G   0% /dev
tmpfs                     32G  893M   31G   3% /dev/shm
tmpfs                     32G  8.9M   32G   1% /run
tmpfs                     32G     0   32G   0% /sys/fs/cgroup
/dev/mapper/centos-root  235G   39G  197G  17% /
/dev/sda2               1014M  179M  836M  18% /boot
/dev/sda1                200M   12M  189M   6% /boot/efi
tmpfs                    6.3G     0  6.3G   0% /run/user/11012
tmpfs                    6.3G     0  6.3G   0% /run/user/0
/dev/mapper/centos-home   10G   33M   10G   1% /home

完工！