Linux uses lvresize to expand or reduce the LV size

Linux uses lvresize to expand or reduce the LV size

Environment: CentOS 6.7

1. Create and mount the directory/u01 and/data

1. create directory Mount node/u01,/data

mkdir -p /{u01,data}

2. Create an lv named lv_u01 with a size of 10 Gb. Divide the space from vg_bkjia. vg_bkjia here is the vg name.

lvcreate -L 10g -n lv_u01 vg_bkjia

3. format it as an ext4 File System

mkfs.ext4 /dev/mapper/vg_bkjia-lv_u01

4. Similarly, create lv_data

lvcreate -L 10g -n lv_data vg_bkjiamkfs.ext4 /dev/mapper/vg_bkjia-lv_data

5. Add mounting information to/etc/fstab to enable automatic mounting upon startup.

vi /etc/fstab/dev/mapper/vg_bkjia-lv_u01      /u01                    ext4    defaults        1 1/dev/mapper/vg_bkjia-lv_data      /data                    ext4    defaults        1 1

Ii. lv resizing:

Method 1: Increase 5 GB directly and write "+ 5 GB"
1. lv expansion 5 GB

lvresize -L +5G /dev/mapper/vg_bkjia-lv_root

2. File System size change

resize2fs /dev/mapper/vg_bkjia-lv_root

Method 2: It turns out to be 10 Gb. Increasing 5 GB is "15 GB"
1. lv expansion to 15 GB

lvresize -L 15G /dev/mapper/vg_bkjia-lv_u01

2. File System size change

resize2fs  /dev/mapper/vg_bkjia-lv_u01

Note: The preceding lvresize command can also be implemented using the lvextend command.

Iii. lv reduction:

1. Uninstall the directory first.

umount /u01

2. Whether this step is determined based on the execution result returned by the next step. See the example below.

e2fsck -f /dev/mapper/vg_bkjia-lv_u01

3. File System size change

resize2fs  /dev/mapper/vg_bkjia-lv_u01 10G

4. lv reduction

lvresize -L 10G /dev/mapper/vg_bkjia-lv_u01

5. Mount all directories recorded in/etc/fstab

mount -a

Appendix: an actual operation process for lv reduction:

[root@LINUXIDC-DB ~]# umount /u01[root@LINUXIDC-DB ~]# resize2fs  /dev/mapper/vg_bkjia-lv_u01 10Gresize2fs 1.41.12 (17-May-2010)Please run 'e2fsck -f /dev/mapper/vg_bkjia-lv_u01' first.[root@LINUXIDC-DB ~]# e2fsck -f /dev/mapper/vg_bkjia-lv_u01e2fsck 1.41.12 (17-May-2010)Pass 1: Checking inodes, blocks, and sizesPass 2: Checking directory structurePass 3: Checking directory connectivityPass 4: Checking reference countsPass 5: Checking group summary information/dev/mapper/vg_bkjia-lv_u01: 12/983040 files (0.0% non-contiguous), 100865/3932160 blocks[root@LINUXIDC-DB ~]# resize2fs  /dev/mapper/vg_bkjia-lv_u01 10Gresize2fs 1.41.12 (17-May-2010)Resizing the filesystem on /dev/mapper/vg_bkjia-lv_u01 to 2621440 (4k) blocks.The filesystem on /dev/mapper/vg_bkjia-lv_u01 is now 2621440 blocks long.[root@LINUXIDC-DB ~]# lvresize -L 10G /dev/mapper/vg_bkjia-lv_u01  WARNING: Reducing active logical volume to 10.00 GiB  THIS MAY DESTROY YOUR DATA (filesystem etc.)Do you really want to reduce lv_u01? [y/n]: y  Size of logical volume vg_bkjia/lv_u01 changed from 15.00 GiB (3840 extents) to 10.00 GiB (2560 extents).  Logical volume lv_u01 successfully resized[root@LINUXIDC-DB ~]# mount -a[root@LINUXIDC-DB ~]# df -hFilesystem            Size  Used Avail Use% Mounted on/dev/mapper/vg_bkjia-lv_root                       15G  1.8G   13G  13% /tmpfs                 499M     0  499M   0% /dev/shm/dev/sda1             190M   36M  145M  20% /boot/dev/mapper/vg_bkjia-lv_data                      9.8G   23M  9.2G   1% /data/dev/mapper/vg_bkjia-lv_u01                      9.8G   23M  9.2G   1% /u01[root@LINUXIDC-DB ~]#

Similarly, the lvreduce command can reduce the lv.
The lvresize Command actually contains the functions of lvextend and lvreduce.

-- Swap extensions managed by LVM, such as increasing by 1024 M:

[Root @ bkjia-DB ~] # Swapoff/dev/mapper/vg_bkjia-lv_swap

[Root @ bkjia-DB ~] # Lvextend-L + 1024 m/dev/mapper/vg_bkjia-lv_swap

[Root @ bkjia-DB ~] # Mkswap/dev/mapper/vg_bkjia-lv_swap

[Root @ bkjia-DB ~] # Swapon/dev/mapper/vg_bkjia-lv_swap

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