Draft Document for Review February 7, 2020 3:15 pm 8464ch05_DisasterRecovery.fm Figure 5-5 shows an optional host connection that can be established to remote Cluster 2  using DWDM or channel extenders. TS7700 Cluster 0 R N D TS7700 Cluster 1 N R D TS7700 Cluster 2 N N R FICON All Virtual devices in cluster 0 are online to host A All Virtual devices in cluster 1 are online to host B Cluster 2 devices are offline Site A – Site / Campus / Region / world Remote DR site Host A Host B FICON WAN Hos Ho TS7 Clu 00 r 0 TS770 Cluste 770 uste TS770 Cluste DWDM, Channel Extension (optional) Host (optional) Figure 5-5 Dual production site with DR Three-cluster high availability production site and DR This model was adopted by many clients. In this configuration, two clusters are in the  production site (same building or separate location within metro area) and the third cluster is  remote at the DR site. Host connections are available at the production site (or sites).  In this configuration, each TS7700D replicates to its local TS7700D peer and the remote  TS7700. Optional copies in both TS7700D clusters provide high availability and cache access  time for the host accesses. At the same time, the remote TS7700 provides DR capabilities  and the remote copy can be remotely accessed, if needed.  214  IBM TS7700 Release 5.0 Guide