Starting virtualization

Data Migrator Administration Guide for Hitachi NAS Platform

Version
14.9.x
Audience
anonymous
Part Number
MK-92HNAS005-32
When starting virtualization, you have two options. You can:
  • Stop at the end of the virtualization phase, and do not migrate any data.
  • Automatically start migrating data once virtualization is complete.
  1. Start the virtualization.
    1. If you want to stop at the end of the virtualization phase, and not automatically migrate any data, use the following command:
      virtualization-path-control -t hnasfs -n assoc1 --start

      Wait for the virtualization to complete. This has the benefit that, at any time, the HNAS can be removed and you can revert back to using the LNAS, without having to reconstruct the data. The disadvantage of this is that the file system performance (seen by clients) will be significantly degraded while in virtualization mode.

    2. To start the data migration, use the command, virtualization-path-control -t hnasfs -n assoc1 --migrate immediately after using virtualization-path-control -t hnasfs -n assoc1 --start. The advantage is that the client access (for files) will automatically transition out of the poorly performing virtualization mode as soon as possible. It should be noted, however, that until the association is deleted and all objects are converted into TitanFile objects (that is, identical to objects that were only ever created on the HNAS outside of an association), the performance will not match that of a "normal" HNAS WFS file system. This is because it is only at this point that the requests by clients against the objects can be completely served in hardware. This has the disadvantage that, if you wish to revert back to using the LNAS on its own, you would have to manually recombine the data that is held on the HNAS with that on the LNAS.
  2. Once the virtualization has been started, it is possible for clients to access the data on the LNAS via the HNAS. This would normally be achieved by creating NFS exports and/or CIFS shares for hnasfs in such a way as to make the data available at the same location the clients were previously accessing: lnas:/existing_data_export. This also requires changing the configuration that is external to the HNAS, for example, DNS records and/or client mount points.
  3. Monitor progress of the virtualization/migration.
  4. Use virtualization-path-list -t hnasfs to display information about the association, including the counts of objects in various states.
  5. Events related to the association are raised in the event log. For example:

    Information: The virtualization path to filesystem hnasfs, association name assoc1, from URI nfs://lnas/existing_data_export has been created.

    Information: The status of the virtualization path to filesystem hnasfs, association name assoc1, has been modified: Virtualization has started.

    Information: The virtualization phase of filesystem hnasfs, association name assoc1 completed.

    Information: The status of the virtualization path to filesystem hnasfs, association name assoc1, has been modified: Migration has started.

    Information: The migration phase of filesystem hnasfs, association name assoc1 completed.

    Information: The virtualization path to filesystem hnasfs, association name assoc1, has been deleted.

  6. If you chose not to automatically proceed with virtualization, you can issue virtualization-path-control -t hnasfs -n assoc1 --migrate at any time, either before or after virtualization has completed. This prevents any further client access to LNAS. You must first ensure that existing_export NFSv3 export is correctly configured on the LNAS.
  7. Once migration has completed, you need to delete the association virtualization-path-delete -t hnasfs -n assoc1.