Communication between cache and home

AFM uses the NFSv3 protocol or the NSD protocol for the communication between clusters.

Communication for caching between clusters is performed by one or more nodes on the cache cluster that are designated as gateway nodes by using the mmchnode command. The target path on the home server must be NFS-exported on one or more nodes in the home cluster, or the home file system must be mounted on the cache cluster by using the NSD protocol. For filesets in the AFM RO mode, the target path at home NFS export can be a read-only or read/write export. The exported path or the home-mounted path of the home cluster is used in the cache cluster as the target while creating a cache fileset.

You can export paths with Kerberos-enabled security levels from home to cache. At cache, configure Kerberos clients at gateway nodes and run the mmchconfig afmEnableNFSSec=yes -i command. Gateway nodes can mount Kerberos-enabled home exports with security levels like sys, krb5, krb5i, krb5p after the afmEnableNFSSec parameter is set to yes at the cluster level.

To configure Kerberos for AFM-DR filesets, the user must enable the read/write access to the AFM-DR secondary. The read/write access can be enabled by setting the afmSecondaryRW parameter value to 'yes'.

Run the following command at the AFM-DR secondary:

# mmchconfig afmSecondaryRW=yes -i

AFM maintains a relationship between cache and home by monitoring home availability and reconnects cache and home.

Note: If a home fileset is removed or deleted, you must remove the export path first and restart NFS at home.