Snapshots are created by CPS using Microsoft Volume Shadow Copy Service (VSS). They contain copies of the Backup Destination at various points in time. Depending on your configuration, a snapshot of the CPS Backup Destination may contain data from multiple Business Servers.
It is not necessary to select the root of the Continuous Protection Server node or to back up snapshots regularly. Most of the data that is captured from snapshot to snapshot is redundant because the majority of the data on the server does not change between snapshots. Back up snapshots only as needed. For example, if a server is running out of disk space, it might be prudent to back up the oldest snapshot for archival.
Snapshot data should be backed up from the Continuous Protection Server node on an as needed basis. This is because of the quantity of redundant data that the snapshots typically contain.