Dell Storage Manager 2020 R1 Administrator's Guide

Using Replication for Disaster Recovery

You can create a disaster recovery configuration in which you replicate data from a primary FluidFS cluster to a target FluidFS cluster that you can fail over to if the primary FluidFS cluster stops responding because of an unexpected failure (hardware, disk, and so on). The target FluidFS cluster could either be used solely for backup for the primary site, or it could have its own NAS volumes sharing data at the target site. In a bi-directional configuration, both FluidFS clusters can act as a failover target for each other.

After you have fixed the reason that caused the original FluidFS cluster to fail, you can manually fail back to the original configuration in which clients access data on the source NAS volume, which in turn replicates to the target NAS volume. Depending on time and bandwidth considerations, failing back to the source NAS volume might take a considerable amount of time to complete.

The following considerations apply when using replication for disaster recovery:

• If the original source NAS volume is no longer available, you can configure the recovery NAS volume to replicate to another NAS volume in the original source FluidFS cluster. However, if the original source NAS volume is available, fail back to it. Failing back to the original source NAS volume usually takes less time than failing back to a new NAS volume. If the FluidFS clusters have a common snapshot, they only need to synchronize the data that changed after that snapshot was created. If no common snapshot is available, or if replicating to a new NAS volume, all data must be synchronized.
• A single FluidFS cluster cannot contain two sets of SMB home shares. Consider the example that Cluster A and Cluster B both have SMB home shares, for different sites or user bases. Cluster A and Cluster B both serve as replication destinations for each other’s NAS volume that contains the SMB home shares. If the administrator tries to fail over Cluster A’s NAS volume that contains SMB home shares to Cluster B, Cluster B rejects this operation because it already has SMB home shares defined on it.