ZFS is an open-source file system and logical volume manager that provides support for high storage capacities and efficient data compression. It includes features such as snapshots and rollbacks, copy-on-write clones, continuous integrity checks, and automatic repair. When installing Ubuntu 19.10 on a server, you have the option to use the ZFS file system (as shown in Figure A). Select this option and then click Install Now. After the installation is complete, reboot and log in. At first glance, you might not notice any difference in the ZFS system. So, how do you use ZFS? I'll show you how to create a snapshot, make changes, and then roll back those changes to the snapshot. The first thing you need to do is find the name of the ZFS dataset you'll be using. I'll be creating a snapshot for my home directory. To list all datasets, you can use the following command:

zfs list

You should see a full list of datasets. The dataset I'll be using is named rpool/USERDATA/jack_bwcn4u. Knowing the dataset name is important because you cannot simply use directory names or paths to create snapshots. To create a snapshot named WED101619, you would use the following command:

sudo zfs snapshot rpool/USERDATA/jack_bwcn4u@WED101619

Creating a snapshot is usually very quick, regardless of how much data is stored in that location. Now, let's make some changes. We'll use the following command to delete the documents folder from our home directory:

rm -rf ~/documents

The documents folder is now gone. Imagine if this folder contained all your work, school, or research documents—what if you didn't have a backup? Since we created a snapshot earlier, you can use the following command to roll back the changes:

sudo zfs rollback rpool/USERDATA/jack_bwcn4u@WED101619

Allow the command enough time to roll back the changes, and voila! The documents folder has returned. Of course, ZFS can do much more, such as cloning snapshots and replication. I encourage you to explore and test these features on your own.