lvreduce 縮小 LV

1. 查看 LV myvdb-vo 掛載在 /reports，大小為 89M ( 100M )。

   [root@kvm10 ~]# df -h
   Filesystem                 Size  Used Avail Use% Mounted on
   /dev/mapper/vg_kvm10-root  4.3G  3.1G  1.2G  73% /
   devtmpfs                   4.0M     0  4.0M   0% /dev
   tmpfs                      853M     0  853M   0% /dev/shm
   tmpfs                      342M  5.0M  337M   2% /run
   tmpfs                      1.0M     0  1.0M   0% /run/credentials/systemd-journald.service
   /dev/vda2                  436M  211M  226M  49% /boot
   tmpfs                      1.0M     0  1.0M   0% /run/credentials/getty@tty1.service
   tmpfs                      171M  8.0K  171M   1% /run/user/0
   /dev/mapper/myvdb-vo        89M   14K   83M   1% /reports
   

2. lvreduce 縮小 LV myvdb-vo 檔案系統為 50M。

   [root@kvm10 ~]# lvreduce -L 50M /dev/myvdb/vo --resizefs
     Rounding size to boundary between physical extents: 52.00 MiB.
     File system ext4 found on myvdb/vo mounted at /reports.
     File system size (100.00 MiB) is larger than the requested size (52.00 MiB).
     File system reduce is required using resize2fs.
     File system unmount is needed for reduce.  缷載
     File system fsck will be run before reduce.  檢查檔案系統
   Continue with ext4 file system reduce steps: unmount, fsck, resize2fs? [y/n]:y
     Reducing file system ext4 to 52.00 MiB (54525952 bytes) on myvdb/vo...
   unmount /reports
   unmount done
   e2fsck /dev/myvdb/vo
   /dev/myvdb/vo: 11/25584 files (9.1% non-contiguous), 12081/102400 blocks
   e2fsck done
   resize2fs /dev/myvdb/vo 53248k
   resize2fs 1.47.1 (20-May-2024)
   Resizing the filesystem on /dev/myvdb/vo to 53248 (1k) blocks.
   The filesystem on /dev/myvdb/vo is now 53248 (1k) blocks long.
   
   resize2fs done
   remount /dev/myvdb/vo /reports
   remount done
     Reduced file system ext4 on myvdb/vo.
     Size of logical volume myvdb/vo changed from 100.00 MiB (25 extents) to 52.00 MiB (13 extents).
     Logical volume myvdb/vo successfully resized.
   

3. 再檢查 LV myvdb-vo 大小為 44M ( 50M )。

   [root@kvm10 ~]# df -h
   Filesystem                 Size  Used Avail Use% Mounted on
   /dev/mapper/vg_kvm10-root  4.3G  3.1G  1.2G  73% /
   devtmpfs                   4.0M     0  4.0M   0% /dev
   tmpfs                      853M     0  853M   0% /dev/shm
   tmpfs                      342M  5.0M  337M   2% /run
   tmpfs                      1.0M     0  1.0M   0% /run/credentials/systemd-journald.service
   /dev/vda2                  436M  211M  226M  49% /boot
   tmpfs                      1.0M     0  1.0M   0% /run/credentials/getty@tty1.service
   tmpfs                      171M  8.0K  171M   1% /run/user/0
   /dev/mapper/myvdb-vo        44M   14K   41M   1% /reports