Manual snapshots are always created on the source HC3 cluster only and are never deleted by the system.
Without remote replication active on a VM, snapshots created using snapshot schedules are also created on the source HC3 cluster only.
With remote replication active, a snapshot schedule repeatedly creates a VM snapshot on the source cluster and then copies that snapshot to the target cluster, where it is retained for a specified number of minutes/hours/days/weeks/months. The default remote replication frequency of 5 minutes, combined with the default retention of 25 minutes, means that by default 5 snapshots are maintained on the target HC3 cluster at any given time.
A VM can only have one snapshot schedule assigned at a time. However, a schedule can contain multiple recurrence rules. Each recurrence rule consists of a replication snapshot frequency (x minutes/hours/days/weeks/months), an execution time (eg. 12:00AM), and a retention (y minutes/hours/days/weeks).