RHEL 8 New Features for Experienced Linux Administrators

On servera, create a VDO volume named vdo1, with the /dev/vdd device. Set its logical size to 20 GB.

1. Log in to servera as the root user.

   [student@workstation ~]$ ssh root@servera

2. Create the vdo1 volume, using /dev/vdd as the device. Use 20 GB as its logical size.

   [root@servera ~]# vdo create --name=vdo1 --device=/dev/vdd --vdoLogicalSize=20G
   Creating VDO vdo1
   Starting VDO vdo1
   Starting compression on VDO vdo1
   VDO instance 0 volume is ready at /dev/mapper/vdo1

3. Verify that the vdo1 volume is available.

   [root@servera ~]# vdo list
   vdo1
   

Verify that both compression and deduplication features are enabled on the vdo1 volume.

1. Verify that deduplication is enabled on the vdo1 volume.

   [root@servera ~]# vdo status -n vdo1 | grep Deduplication
     Deduplication: enabled

2. Verify that compression is enabled on the vdo1 volume.

   [root@servera ~]# vdo status -n vdo1 | grep Compression
     Compression: enabled

Create an XFS file system on the vdo1 volume, and mount it on /mnt/vdo1.

1. Create an XFS file system on the vdo1 volume. Wait until the system registers the device node.

   [root@servera ~]# mkfs.xfs -K /dev/mapper/vdo1
   ...output omitted...
   [root@servera ~]# udevadm settle

2. Create the /mnt/vdo1 directory.

   [root@servera ~]# mkdir -m 1777 /mnt/vdo1

3. Mount the vdo1 volume on /mnt/vdo1.

   [root@servera ~]# mount /dev/mapper/vdo1 /mnt/vdo1/

Create several copies of a file on the vdo1 volume to verify how deduplication takes place.

1. Verify the status of the vdo1 volume. When created, a VDO volume reserves around 3 or 4 GB for itself.

   [root@servera ~]# vdostats --human-readable
   Device                    Size      Used Available Use% Space saving%
   /dev/mapper/vdo1         20.0G      4.0G     16.0G  20%           98%

2. Download the http://content.example.com/rhel8.0/x86_64/dvd/images/install.img file, and copy it to the /mnt/vdo1 directory. It may take up to a minute to download it.

   [root@servera ~]# wget \
   > http://content.example.com/rhel8.0/x86_64/dvd/images/install.img
   [root@servera ~]# cp install.img /mnt/vdo1

3. Verify the status of the vdo1 volume to see the changes in Use%, and Space saving%.

   [root@servera ~]# vdostats --human-readable
   Device                    Size      Used Available Use% Space saving%
   /dev/mapper/vdo1         20.0G      4.4G     15.6G  22%            3%

4. Create another copy of the install.img file in the /mnt/vdo1 directory.

   [root@servera ~]# cp install.img /mnt/vdo1/install.img.2

5. Verify the status of the vdo1 volume, and the size increase of Space saving%.

   [root@servera ~]# vdostats --human-readable
   Device                    Size      Used Available Use% Space saving%
   /dev/mapper/vdo1         20.0G      4.5G     15.5G  22%           50%

6. Create an additional copy of the install.img file in the /mnt/vdo1 directory.

   [root@servera ~]# cp install.img /mnt/vdo1/install.img.3

7. Verify the status of the vdo1 volume, and the size increase of Space saving%.

   [root@servera ~]# vdostats --human-readable
   Device                    Size      Used Available Use% Space saving%
   /dev/mapper/vdo1         20.0G      4.5G     15.5G  22%           67%

Remove the vdo1 volume. When done, log out from servera.

1. Unmount the vdo1 volume.

   [root@servera ~]# umount /mnt/vdo1

2. Remove the vdo1 volume.

   [root@servera ~]# vdo remove --name=vdo1
   Removing VDO vdo1
   Stopping VDO vdo1
               

3. Log out from servera.

   [root@servera ~]# exit
   [student@workstation ~]$