The failover mapping for AFM NFS targets

The failover mapping provides NFS resiliency for Active File Management (AFM) filesets that use mapped NFS export targets by selecting another available export server when the current server becomes unavailable.

The failover mapping is an AFM feature that maintains data synchronization between the cache and home clusters when a mapped home NFS export server becomes unavailable. This applies only to AFM filesets that use a target map for exported NFS targets.

Without the failover mapping, AFM can detect that a mapped NFS export server is unavailable, but AFM continues to depend on the failed server assignment. As a result, synchronization can stop until a working export server is selected through configuration changes or recovery actions.

When the afmFailoverMap parameter is enabled at the fileset level, and the afmParallelMounts parameter is enabled at the cluster level, AFM evaluates the NFS export servers that are listed in the target map and uses the next available server for the fileset. This behavior reduces disruption when a home export server fails and synchronization is continues through another mapped export server.

The target map defines the relationship between gateway nodes in the cache cluster and NFS export servers in the home cluster. AFM uses that mapping to determine which alternate export servers are available for the fileset.

If another mapped export server is available, AFM switches data synchronization to that server. If no mapped export server is available, AFM moves the fileset to the unmounted state.

The valid values for the afmFailoverMap parameter are yes and no. The default value is no.

To enable the failover mapping, see Enabling the failover mapping.