Converting GPFS filesets to AFM DR

The IBM GPFS-independent filesets to primary or secondary filesets conversion can be done for the replication.

1. By using the trucking method, ensure that the secondary site has the same data as the primary site.

   An existing IBM GPFS-independent fileset can be converted to primary or secondary. If the fileset on the primary site has data, the secondary site must be synchronized with the same data. This process is called trucking. The trucking must be inband.

   Inband trucking

   Copying the data from the primary to the secondary while you are setting up the relationship. The inband trucking is limited by the network bandwidth between the primary and the secondary.

   The conversion of a regular independent fileset to AFM primary with the mmafmctl command must be performed by specifying the --check-metadata option. This option verifies that the fileset does not contain objects with attributes that are not allowed in a primary fileset. These objects are as follows:

   • Special files (such as devices)
   • Dependent fileset
   • Clones where a source belongs to a snapshot.
2. Before the actual conversion, get the primary ID of the GPFS fileset by using the mmafmctl getprimaryid command on the GPFS fileset.
3. Convert the fileset on the secondary site to a secondary and set the primary ID by using the mmchfileset or mmafmctl command with the convertToSecondary option.

   If NFS is used to define an AFM target on the primary site, ensure that the NFS export on the secondary site is accessible on the primary. If GPFS protocol is used for the target, the secondary file system must be remote-mounted on the primary site.

   Note: If you are establishing the secondary by using the out-of-band option, do the following steps:

   1. Complete the data copy.
   2. Ensure that the primary and the secondary have the same data before you configure the secondary with the unique ID of the primary.
4. Restart the NFS server on the secondary site. If the NFS server is used by other application, reexport the directories on the secondary site by using the exportfs -ra option.
5. Convert the fileset on the primary site to a primary by using mmafmctl command. Run on the primary cluster. Gateway nodes must be defined in the primary site and the file system must be mounted on all gateway nodes before this conversion. Run the mmafmctl command with the convertToPrimary option.

   mmafmctlDevice convertToPrimary-j FilesetName 
   [ --afmtarget Target { --inband | --secondary-snapname SnapshotName }] 
     [ --check-metadata | --nocheck-metadata ] [--rpo RPO] [-s LocalWorkDirectory

   The --afmtarget option and the --inband option are mandatory options for the first conversion command on the fileset. The conversion can be interrupted due to unforeseen reasons or in case of rare errors when psnap0 creation is not successful. In such cases, the fileset is converted to a primary but the state is PrimInitFail.

   Based on the reason behind the failure, the administrator must rerun the conversion command without any argument. Alternatively, the fileset can be converted back to normal GPFS filesets and converted again by using the conversion command with arguments.

   The --afmtarget option mentions the fileset path on the secondary site.

   The --inband option is used for the inband trucking. Primary ID is generated and the first RPO snapshot psnap0 is created. The entire data on the snapshot is queued to the secondary. After the data is replayed on the secondary after Step 3 (following), that is, the primary and secondary are connected, it creates a psnap0 snapshot on the secondary ensuring that the psnap0 on the primary and the secondary are the same. Now, you can consider that a relationship is established.

   Before the conversion, the --check-metadata option checks if the disallowed types such as immutable/append-only files, clones where the source belongs to a snapshot, are present in the GPFS fileset on the primary site. If the disallowed types still exist on the primary site, the conversion fails. The --check-metadata option is not mandatory and scans the entire fileset to verify its contents. If the fileset is known to be permissible for conversion, it can be excluded and it must be used whenever you have a doubt. This option is the default option.

   The --no check-metadata option is used to proceed with conversion without checking for the disallowed types.

   The --rpo option specifies the RPO interval in minutes for this primary fileset. By default, RPO is disabled. You can use the mmchfileset command to modify the afmRPO parameter value of the AFM DR fileset. The --secondary-snapname option is not applicable for the AFM or GPFS filesets conversion. This option is used while you are establishing a new primary, as discussed in subsequent sections.

   Gateway node assignments must be finalized and done preferably before conversion of GPFS or AFM filesets to the primary site. If no gateway is present on the primary cluster during conversion, then primary fileset might remain in the PrimInitFail state.