A large customer wants to have three copies of a 15 TB database created with ShadowImage during a three week cycle (60 TB total capacity). They want to have fast disk-based recovery option from any…

A large customer wants to have three copies of a 15 TB database created with ShadowImage during a three week cycle (60 TB total capacity). They want to have fast disk-based recovery option from any of the preceding three weeks but without the expense of using Tier1 or Tier2 storage. Some performance impact is acceptable during the recovery as disk-based recovery is much faster than the previous tape-based scheme. What is the appropriate solution?