Configuring for disaster recovery

In a grid configuration that supports DR, TS7700 Clusters reside in different locations, should a natural or human-caused event render the production TS7700 Cluster unavailable. Production and DR clusters are separated by a distance that is dictated by DR requirements established by your company. Only the TS7700 Grid interconnection and the TSSC network connect the local site to the DR site. No host connectivity exists between local hosts and the FICON® channels on the TS7700 at the DR site. As part of planning a TS7700 Grid configuration to address this solution, you must consider the following:

• Plan for the necessary WAN infrastructure and bandwidth to meet the copy requirements that you need. You generally require more bandwidth if you are primarily using a copy consistency point of RUN since any delays in copy time caused by bandwidth limitations result in an elongation of job run times. If you have limited bandwidth available between sites, use the deferred copy consistency point or copy only the data that is critical to the recovery of your key operations.
• Plan for backup host connectivity at your DR site with sufficient resources to perform your critical workloads.
• Design and code the Data Facility System Managed Storage (DFSMS) Automatic Class Selection routines to control what data gets copied and by which copy consistency point.
• Prepare procedures that your operators would execute if the local site became unusable. The procedures would include such tasks as bringing up the DR host, varying the virtual drives online, and enabling one of the ownership takeover modes against the failed primary TS7700 Cluster.
• If the local TS7700 Cluster becomes unavailable, there is no local host access to the data in the TS7700 Cluster at the DR site.