There are essentially two types of Point-in-Time copies:
– Full copy Point-in-Time Copies – (Mirror)
• Requires 100% of the space of the Primary image • Must copy all the data from primary to copy before using it • Completely separate data areas – no common data sharing
– Snapshot Copies
• Available “instantly” – because it doesn’t have to make an initial copy
• Uses less space, since only changed data is copied from the primary
• Data in primary and copy are shared in order to make up the Point-in-Time image
• Ideal for short-term backup and recovery purposes
We always start with point in time copies because whether or not we are going to use a media server to create our tape backup we always need a consistent usable copy of data.
A point in time copy is a consistent usable copy of data at that point in time.