Dell NetWorker 19.9 Administration Guide

Strategies for cloning

You can use scheduled cloning or action based (automatic) cloning to manage your data.

• Scheduled cloning—You can have a policy, and a workflow followed by a clone action. The workflow is associated with a dynamic group. In other words, a Query or Save set protection group.
• Action based (automatic) cloning—You can have a policy, and a workflow followed by a backup and a clone action. The clone action can be configured as concurrent or sequential.
  • Sequential—When the backup action configured for a policy or workflow is triggered, backup copies are created in the selected backup pool. However, the clone action is triggered only after backup copies are created for all the selected save sets. For example, If there are save sets numbered 1 to 100, backup copies are created in order. The clone action is triggered only after the backup copy is created for save set 100.
    NOTE:Sequential cloning is the preferred cloning method.
  • Concurrent—When the backup action configured for a policy or workflow is triggered, backup copies are created in the selected backup pool. The clone action is triggered even if only a single backup copy is created from the selected save sets. For example, If there are save sets numbered 1 to 100, backup copies are created in order. The clone action for save set 1 is triggered when the backup copy for save set 1 is created. However, for performance optimization, clones for save sets are triggered in batches.

You can also use automated multistreaming (AMS) when cloning your data to speed up the replication process.

If you are replicating save sets between two Data Domain devices on different machines, replication using NetWorker takes longer because each save set uses a single stream. The use of automated multistreaming (AMS) splits up large files (files larger than 3.5 GiB) into multiple smaller 2 GB slices, replicates those slices individually, and re-creates the original large file on the destination DDR using those slices.

The following diagram illustrates replication using AMS.

AMS is supported only if:

• Both the source and destination Data Domain systems support the virtual synthetic capability (DDOS 5.5 and later). It can be validated through ddboost option show command as shown below:

  ddboost@localhost# ddboost option show  
  Option                        Value
  ----------------------        -------
  distributed-segment-processing enabled
  virtual-synthetics             enabled
  fc                             enabled
  global-authentication-mode     none
  global-encryption-strength     none

• The save set file being copied is large enough for the use of AMS to provide an improvement over normal replication.
• All save set types other than VBA, vProxy, and synthetic full. The exception is for Microsoft NMM Exchange module save sets, where AMS is used even though it uses BBB and synthetic full.

Enable AMS, if the underlying bandwidth between two DDRs is 10 Gbps. Because the use of AMS creates multiple streams, there must be enough bandwidth between the two DDRs being used for the clone workflow.

The NSR cloneconfig resource enables you to add debug flags, control cloning sessions, and use the AMS functionality.

By default, AMS is disabled. To enable AMS, ensure that the Ams enabled flag is set to Yes.

The following table describes the NSR cloneconfig resource details and their default values.

Max client threads * Max threads per client <= max_concurrency
max_concurrency = MIN(30, dest_pool_parallelism, available_stream_count)