Modes and concepts

AFM DR uses the same underlying infrastructure as AFM. AFM DR is characterized by two modes; the fileset in the primary cluster uses the primary mode, and the fileset in the secondary cluster uses the secondary mode.

AFM DR is supported over both NFS v3 and GPFS™ protocol. The primary fileset is owned by the MDS, which communicates with the NFS server on the secondary side. The primary-secondary relationship is strictly one-to-one.

AFM revalidation does not apply to primary filesets. All files are always cached, because primary is the only writer and secondary is in the read-only mode. After the applications failover to secondary and are failed back to primary, all updated directories and files with contents on the secondary site are pulled to the primary site by the failback process. The asynchronous delay is applicable to primary filesets and can be configured.

You can convert the SW/IW relationship to a DR relationship. However, you cannot convert a DR relationship to a SW/IW relation.