Recovery capabilities by topology
The three basic topologies that you can deploy with the IBM Storage Scale pattern provide different recovery capabilities.
The primary quality of service provided by the deployed IBM Storage Scale pattern environment is to allow IBM Storage Scale Clients to have access to the file system when part of the IBM Storage Scale Cluster goes down.
The IBM Storage Scale environment also supports restoring the configuration when pieces of the configuration go down, either temporarily, or when there is permanent loss.
The recovery steps that you take in these situations depends on the type of outage there has been and the extent of the loss of IBM Storage Scale cluster disks (LUNs) or nodes (NSD servers and virtual machines).
The Primary deployment topology
The Mirrored deployment topology
In a IBM Storage Scale Mirror configuration, the IBM Storage Scale Mirror instance is attached to a IBM Storage Scale Primary instance. Data that a IBM Storage Scale Client writes to the IBM Storage Scale file system is written to both the Primary instance and the Mirror instance. This topology supports active replication of data as well as failover.
Because the Primary configuration and the Mirror configuration are operating in separate geographic locations, this topology supports disaster recovery operations. In addition to the Primary and Mirror deployments, a Tiebreaker deployment is required to manage IBM Storage Scale cluster operations in the event that either the Primary or Mirror configuration is lost. With either the Primary or Mirror instance and the Tiebreaker instance in action, the IBM Storage Scale cluster continues to operate and serve data to the IBM Storage Scale Clients using the cluster.