If you choose this automated method, you prepare for the upgrade using a script. This script stops Logging Node services on all devices in the cluster, and creates a snapshot that preserves your existing Logging Node data. This method makes it much more likely that the upgrade process goes smoothly.
You need snapshots so you can restore the Logging Node data, especially after performing software upgrades.
When snapshots are created, they need to be stored on a machine other than the Logging Node that stores the data. You define the location for the snapshot by editing the fstab file on each device in your Logging Node cluster.
Running the upgrade preparation script is the safest way to prepare for the Logging Node upgrade. Using the automated script eliminates the chance of either omitting a step, or typing in an incorrect value, either of which could lead to failure for the entire upgrade process.