Data replication from one destination to another in a series (cascading)

You can replicate data from a SnapMirror destination to another storage system using SnapMirror. Therefore, a storage system that is a destination for one SnapMirror relationship, can act as the source for another SnapMirror relationship. This is useful when you need to copy data from one site to many sites.

• Supported SnapMirror cascade configurations
  There are different types of SnapMirror available to you. However, the different types of SnapMirror cannot be used at different stages in a cascade.
• Supported SnapMirror three-hop cascade configurations
  Only certain combinations of SnapMirror replication types are supported for three-hop cascade configurations.
• Sample cascade setup
  
• How SnapMirror handles Snapshot copies for cascading destinations
  SnapMirror retains the Snapshot copies on the original source volume needed for transfers to destinations further down the line. Snapshot copies that are still needed by a destination are labeled “snapmirror” in the output of the snap list command. SnapMirror deletes the Snapshot copies it no longer needs.
• Listing SnapMirror destinations for a volume in a cascading series
  You can use the snapmirror destinations command to display the destinations for a volume in a cascading series.
• Restructuring a cascade
  You might restructure a cascade to balance loading of your systems; to use a storage system or volume for a different purpose; or to perform upgrades, maintenance, or repairs.