NetWorker: Introduction to Save Set Cloning

About Save set Cloning in NetWorker.

Cloning allows administrators to make redundant copies of complete save sets to other media for redundancy or offsite protection. It helps confirm that the original data structure is readable and the media is valid. However, it cannot guarantee data integrity; only a recovery verifies the data.

Cloning-related Terminology

• Save set: A definition of backup data, such as a file system, database definition, or disaster recovery data
• Cloning: Making an identical, redundant copy of existing, complete save sets
• Instance: Original backup or clone copy of a save set on media - an instance of a save set is a copy (each on separate volume)
• Volume: A piece of media to which save set instances are written (media types may be different)
• Label: Metadata written to the head of the volume describing its properties - labels are required before NetWorker accesses volumes
• Pool: Logical grouping of volumes for either backup OR cloning, usually all being of the same media type
• Device: Usually, tape, disk, or Data Domain where a volume is read and written after being mounted
• Mount: Logical process of verifying a volume s label in a device and readying for access
• Storage Node: A designated NetWorker host which accesses devices (NetWorker Server is a Storage Node by default)

How Cloning Works

At its most basic level, cloning is a partial recovery of a save set passed directly to a new backup. It does not decode the data but rather rewrites the blocks to the new destination clone pool volume. Cloning requires:

• Source and destination media, to read from and write to, respectively
• Source and destination devices, to perform the aforementioned read and write operations
• Source and destination Storage Nodes (since the source and destination devices may not both be accessible by a single Node)

While the destination clone pool must be specified, the other elements are chosen using internal logic unless specified by the administrator in the properties of the Clone action or using the nsrclone command.

Cloning Methodology

To understand the various ways to implement cloning in NetWorker, first consider the workflow components available:

• Policy: A broad collection of Workflows
• Workflow: A series of Actions to be performed against a Group
• Group: A collection of clients, save sets, or objects Actions are performed against
• Action: An operation to be performed against a Group (such as backup, cloning, so forth)

In NetWorker, Cloning is an Action and as such can be configured or run in various ways.

Cloning For Your Needs

NetWorker allows a great deal of freedom to determine what, how and when you want to clone your data:

• Cloning immediately after successful backup - As a Clone Action following a Backup Action in a Workflow
• Cloning in multiple stages - Add successive Clone Actions to a single Workflow to clone to multiple targets
• Cloning on schedule based on specific query criteria of existing save sets - As a Clone Action in a Workflow using a Save set-type Group
• Ad-hoc cloning of full volumes, single or multiple designated save sets - From Media section, using Save set Query or Volumes container
• Deleting source save set after successful cloning - A tickbox in Clone Action properties (previously known as Staging)

Advanced Cloning Technologies

Magnetic tape backup continues to serve as a standard for backup and long‑term offsite storage, offering a mature, efficient, and cost‑effective method of data protection. Disk solutions are preferred for nearline storage, are faster and simpler to manage.

Clone Controlled Replication with Data Domain devices.

Data Domain devices are an advanced backup technology solution for NetWorker, but also an advanced cloning feature. Cloning between two Data Domain-type devices in NetWorker automatically invokes Data Domain replication, which is more efficient than normal cloning methods. Also called Enhanced Cloning, this method copies only missing deduplicated chunks and metadata to the destination, allowing it to rebuild the file using existing data. This means that only a fraction of the data is sent, often.

Using CloudBoost to clone to the cloud.

CloudBoost allows NetWorker administrators to add a CloudBoost virtual appliance to their Datazone to act as a NetWorker Storage Node. Data cloned to devices created on this node are compressed and deduplicated before being sent to a public or private cloud storage provider. Usually this data is also redundantly protected, adding an extra layer of security to an excellent long-term storage option.

Troubleshooting:

See: NetWorker: How to troubleshoot Scheduled Cloning Issues