Merge pull request #19878 from lujun9972/add-MjAyMDA5MjIgSG93IHRvIFJlZHVjZS1TaHJpbmsgTFZNLXMgKExvZ2ljYWwgVm9sdW1lIFJlc2l6ZSkgaW4gTGludXgubWQK

选题[tech]: 20200922 How to Reduce/Shrink LVM’s (Logical Volume Resize)…
2024-12-26 21:30:55 +08:00 · 2020-10-16 19:45:18 +08:00 · 2020-10-16 19:45:18 +08:00 · 65dc8ec18b
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+[#]: collector: (lujun9972)
+[#]: translator: ( )
+[#]: reviewer: ( )
+[#]: publisher: ( )
+[#]: url: ( )
+[#]: subject: (How to Reduce/Shrink LVM’s (Logical Volume Resize) in Linux)
+[#]: via: (https://www.2daygeek.com/reduce-shrink-decrease-resize-lvm-logical-volume-in-linux/)
+[#]: author: (Magesh Maruthamuthu https://www.2daygeek.com/author/magesh/)
+
+How to Reduce/Shrink LVM’s (Logical Volume Resize) in Linux
+======
+
+Reducing/Shrinking the logical volume is the highest risk of data corruption.
+
+So try to avoid this kind of situation if possible, but go ahead if you have no other options.
+
+It is always recommended to make a backup before shrinking an LVM.
+
+When you are running out of disk space in LVM, you can make some free space on the volume group by reducing the exsisting LVM that no longer uses the full size, instead of adding a new physical disk.
+
+**Make a note:** Shrinking is not supported on a `GFS2` or `XFS` file system.
+
+If you are new to Logical Volume Management (LVM), I suggest you start with our previous article.
+
+  * **Part-1: [How to Create/Configure LVM (Logical Volume Management) in Linux][1]**
+  * **Part-2: [How to Extend/Increase LVM’s (Logical Volume Resize) in Linux][2]**
+
+
+
+![][3]
+
+Reducing the logical volume involves the below steps.
+
+  * Unmount the file system.
+  * Check the file system for any errors.
+  * Shrink the file system size.
+  * Reduce the logical volume size.
+  * Re-check the file system for errors (Optional).
+  * Mount the file system
+  * Check the reduced file system size
+
+
+
+**For instance;** You have a **100GB** LVM that no longer uses the full size, you want to reduce it to **80GB** so **20GB** can be used for other purposes.
+
+```
+# df -h /testlvm1
+
+Filesystem              Size Used Avail Use% Mounted on
+/dev/mapper/vg01-lv002  100G 15G  85G   12%  /testlvm1
+```
+
+### 1) Unmount the file system
+
+Use the umount command to unmount the file system.
+
+```
+# umount /testlvm1
+```
+
+### 2) Check the file system for any Errors
+
+Check the file system for any errors using the e2fsck command.
+
+```
+# e2fsck -f /dev/mapper/vg01-lv002
+
+e2fsck 1.42.9 (28-Dec-2013)
+Pass 1: Checking inodes, blocks, and sizes
+Pass 2: Checking directory structure
+Pass 3: Checking directory connectivity
+Pass 4: Checking reference counts
+Pass 5: Checking group summary information
+/dev/mapper/vg01-lv002: 13/6553600 files (0.0% non-contiguous), 12231854/26212352 blocks
+```
+
+### 3) Shrink the file system.
+
+The below command will reduce the **“testlvm1”** file system from **100GB** to **80GB**.
+
+**Common syntax for file system resize (resize2fs).**
+
+```
+resize2fs [Existing Logical Volume Name] [New Size of File System]
+```
+
+The actual command is as follows.
+
+```
+# resize2fs /dev/mapper/vg01-lv002 80G
+
+resize2fs 1.42.9 (28-Dec-2013)
+Resizing the filesystem on /dev/mapper/vg01-lv002 to 28321400 (4k) blocks.
+The filesystem on /dev/mapper/vg01-lv002 is now 28321400 blocks long.
+```
+
+### 4) Reduce the Logical Volume (LVM)
+
+Now reduce the logical volume (LVM) size using the lvreduce command. The below command **“/dev/mapper/vg01-lv002”** will shrink the Logical volume (LVM) from 100GB to 80GB.
+
+**Common syntax for LVM Reduce (lvreduce)**
+
+```
+lvreduce [New Size of LVM] [Existing Logical Volume Name]
+```
+
+The actual command is as follows.
+
+```
+# lvreduce -L 80G /dev/mapper/vg01-lv002
+
+WARNING: Reducing active logical volume to 80.00 GiB
+THIS MAY DESTROY YOUR DATA (filesystem etc.)
+Do you really want to reduce lv002? [y/n]: y
+Reducing logical volume lv002 to 80.00 GiB
+Logical volume lv002 successfully resized
+```
+
+### 5) Optional: Check the file system for any Errors
+
+Check the file system again if there are any errors after LVM has been reduced.
+
+```
+# e2fsck -f /dev/mapper/vg01-lv002
+
+e2fsck 1.42.9 (28-Dec-2013)
+Pass 1: Checking inodes, blocks, and sizes
+Pass 2: Checking directory structure
+Pass 3: Checking directory connectivity
+Pass 4: Checking reference counts
+Pass 5: Checking group summary information
+/dev/mapper/vg01-lv002: 13/4853600 files (0.0% non-contiguous), 1023185/2021235 blocks
+```
+
+### 6) Mount the file system and check the reduced size
+
+Finally mount the file system and check the reduced file system size.
+
+Use the mount command to **[mount the logical volume][4]**.
+
+```
+# mount /testlvm1
+```
+
+Check the newly mounted volume using the **[df command][5]**.
+
+```
+# df -h /testlvm1
+
+Filesystem              Size Used Avail Use% Mounted on
+/dev/mapper/vg01-lv002  80G  15G  65G   18%  /testlvm1
+```
+
+--------------------------------------------------------------------------------
+
+via: https://www.2daygeek.com/reduce-shrink-decrease-resize-lvm-logical-volume-in-linux/
+
+作者：[Magesh Maruthamuthu][a]
+选题：[lujun9972][b]
+译者：[译者ID](https://github.com/译者ID)
+校对：[校对者ID](https://github.com/校对者ID)
+
+本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
+
+[a]: https://www.2daygeek.com/author/magesh/
+[b]: https://github.com/lujun9972
+[1]: https://www.2daygeek.com/create-lvm-storage-logical-volume-manager-in-linux/
+[2]: https://www.2daygeek.com/extend-increase-resize-lvm-logical-volume-in-linux/
+[3]: data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7
+[4]: https://www.2daygeek.com/mount-unmount-file-system-partition-in-linux/
+[5]: https://www.2daygeek.com/linux-check-disk-space-usage-df-command/