NetWorker 19.7 Snapshot Management Integration Guide

Example of a snapshot and clone to storage media

The following figures illustrate two variations of the flow of data during a snapshot and clone operation in a typical NetWorker snapshot environment.

The process flow is as follows:

1. The application host processes its production data by writing to one or more source volumes on an attached storage array.
   NOTE The application host can run NMDA or NMSAP. As a common practice for these modules, the application host can have its own NetWorker storage node, which makes the application host also the mount host.
2. At a scheduled time, NetWorker creates a snapshot of the production data on a different volume on the storage array or on a different array:
   1. NetWorker policies and client resource settings identify which data on the application host requires a snapshot.
   2. NetWorker synchronizes the source LUNs with the target LUNs. The source LUNs contain the production data volumes. To ensure consistency, NetWorker together with NMDA or NMSAP quiesces the database, or if just file systems, quiesces and flushes data before taking the snapshot.
   3. The storage array splits or fractures the target snapshot LUN from the production LUNs. This process creates a fully usable snapshot on the snapshot volume.
3. NetWorker optionally mounts the completed snapshot on the mount host to validate that the snapshot can be restored.

   The choice of mount host depends on the storage network configuration with consideration of the data processing speed and the bandwidth load on the different possible hosts. For example, the mount host can be one of the following:

   • A NetWorker storage node or the application host as shown in Example of a snapshot and clone to storage media.
   • A remote mount host with the NetWorker client and extended client software installed.
   NOTE If the NetWorker client resource settings specify the Client Direct and Data Domain Boost options, on-client data deduplication processing occurs on the mount host during the clone operations to conventional media.
4. NetWorker manages the snapshot according to the options in the client resource settings and NetWorker policy resource:
   • If NetWorker clones the snapshot to conventional storage media, the snapshot data becomes available for additional NetWorker clone operations and conventional NetWorker restore operations.

     The NetWorker Administration Guide provides details of storage media configurations.

   • If NetWorker does not clone the snapshot but retains the snapshot on the storage array or the Data Domain (ProtectPoint snapshot), the snapshot is available for restore, rollback, or clone. NetWorker retains the snapshot on the storage array only until it expires or until NetWorker must delete it to create snapshots, as specified by the NetWorker policy.