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LVM Comprehensive Experiment

Popularity：150 ℃/2024-07-30 10:55:50

experimental objective

  • Create and manage an LVM volume group (VG).
  • Create, expand, and shrink logical volumes (LVs) in volume groups.
  • Create and use snapshots.

experimental environment

  • Linux servers
  • Three available disk partitions./dev/sdb1, /dev/sdb2, and/dev/sdb3

experimental step

Step 1: Install the LVM Tool

Make sure the LVM tool is installed. If not, install it:

yum install lvm2 -y

Step 2: Create a Physical Volume (PV)

utilization/dev/sdb1, /dev/sdb2, and/dev/sdb3 Create a physical volume.

pvcreate /dev/sdb1
pvcreate /dev/sdb2
pvcreate /dev/sdb3

Step 3: Viewing Physical Volume Information

pvs
pvdisplay

Step 4: Create a Volume Group (VG)

Create a volume group with all three physical volumesmyvg。

vgcreate myvg /dev/sdb1 /dev/sdb2 /dev/sdb3

Step 5: Viewing Volume Group Information

vgs
vgdisplay

Step 6: Volume Group Expansion and Reduction

[root@localhost ~]# vgs
  VG   #PV #LV #SN Attr   VSize   VFree  
  myvg   3   0   0 wz--n- <14.99g <14.99g
  rhel   1   2   0 wz--n- <19.00g      0 
[root@localhost ~]# pvcreate /dev/sdb{5,6}
  Physical volume "/dev/sdb5" successfully created.
  Physical volume "/dev/sdb6" successfully created.
[root@localhost ~]# vgextend myvg /dev/sdb{5,6}
  Volume group "myvg" successfully extended
[root@localhost ~]# vgs
  VG   #PV #LV #SN Attr   VSize   VFree 
  myvg   5   0   0 wz--n-  18.98g 18.98g
  rhel   1   2   0 wz--n- <19.00g     0 
[root@localhost ~]# vgreduce myvg /dev/sdb6
  Removed "/dev/sdb6" from volume group "myvg"
[root@localhost ~]# vgs
  VG   #PV #LV #SN Attr   VSize   VFree 
  myvg   4   0   0 wz--n-  16.98g 16.98g
  rhel   1   2   0 wz--n- <19.00g     0 
[root@localhost ~]#

Step 7: Create a Logical Volume (LV)

Create two logical volumes:mylv1 cap (a poem)mylv2。

[root@localhost ~]# lvcreate -l 10 -n mylv1 myvg
  Logical volume "mylv1" created.
[root@localhost ~]# lvcreate -L 100M -n mylv2 myvg
  Logical volume "mylv2" created.

Step 8: Viewing Logical Volume Information

lvs
lvdisplay

Step 9: Formatting Logical Volumes

Format the newly created logical volume asext4 File System.

mkfs.ext4 /dev/myvg/mylv1
mkfs.ext4 /dev/myvg/mylv2

Step 10: Mounting a Logical Volume

Create a mount point and mount the logical volume.

[root@localhost ~]# mkdir -p /mydir/mylv1
[root@localhost ~]# mkdir -p /mydir/mylv2
[root@localhost ~]# mount /dev/myvg/mylv1 /mydir/mylv1
[root@localhost ~]# mount /dev/myvg/mylv2 /mydir/mylv2

Step 11: Verify the Mount

[root@localhost ~]# df -Th
Filesystem Type Capacity Used Available Used % Mount Points
/dev/mapper/rhel-root xfs 17G 3.8G 14G 22% /
devtmpfs devtmpfs 897M 0 897M 0% /dev
tmpfs tmpfs 912M 0 912M 0% /dev/shm
tmpfs tmpfs 912M 9.0M 903M 1% /run
tmpfs tmpfs 912M 0 912M 0% /sys/fs/cgroup
/dev/sda1 xfs 1014M 179M 836M 18% /boot
tmpfs tmpfs 183M 20K 183M 1% /run/user/0
/dev/mapper/myvg-mylv1 ext4 35M 782K 32M 3% /mydir/mylv1
/dev/mapper/myvg-mylv2 ext4 93M 1.6M 85M 2% /mydir/mylv2

Step 12: Extending a Logical Volume (LV)

extensionsmylv1 The size of the

[root@localhost ~]# lvextend -L +60M /dev/myvg/mylv1
[root@localhost ~]# resize2fs /dev/myvg/mylv1

Step 13: Reduce Logical Volume (LV)

First unmount the logical volume, then check and resize the file system, and finally resize the logical volume.

[root@localhost ~]# umount /mydir/mylv1
[root@localhost ~]# e2fsck -f /dev/myvg/mylv1
[root@localhost ~]# resize2fs /dev/myvg/mylv1 50M
[root@localhost ~]# lvreduce -L -50M /dev/myvg/mylv1
[root@localhost ~]# mount /dev/myvg/mylv1 /mydir/mylv1
[root@localhost ~]# lvs

Step 14: Creating a Snapshot

establishmylv2 snapshotsmysnop。

[root@localhost ~]# echo "test data" > /mydir/mylv2/newfile
[root@localhost ~]# lvcreate -L 20M -s -n mysnop /dev/myvg/mylv2
[root@localhost ~]# lvs

Step 15: Recovering Data Using Snapshots

Assuming that themylv2 Some data has been written to it and now it needs to be restored to the state it was in at the time of the snapshot.

[root@localhost ~]# ls /mydir/mylv2/
[root@localhost ~]# rm -rf /mydir/mylv2/newfile
[root@localhost ~]# umount /mydir/mylv2
[root@localhost ~]# lvconvert --merge /dev/myvg/mysnop
[root@localhost ~]# mount /dev/myvg/mylv2 /mydir/mylv2
[root@localhost ~]# ls /mydir/mylv2/
[root@localhost ~]# lvs

Step 16: Logical Volume Volume Group Deletion

When the experiment is complete, clean up all resources created.

umount /mydir/mylv1
umount /mydir/mylv2
lvremove /dev/myvg/mylv1
lvremove /dev/myvg/mylv2
vgremove myvg
pvremove /dev/sdb1 /dev/sdb2 /dev/sdb3 /dev/sdb5

caveat

  • Make sure to back up important data before performing any operations involving data.
  • Be sure to unmount the logical volume first when performing an expansion or reduction operation on the logical volume.
  • Before shrinking a logical volume, make sure you perform a file system check first (e2fsck) and resize the file system (resize2fs)。

After completing the above steps, you should be able to master the basic management and operation techniques of LVM. Please make sure to record important output results and observed phenomena during the experiment for subsequent analysis and learning.

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