File System Snapshot

Overview

File System Snapshot, a built-in feature of the UNIX operating system, is supported by the Quick Recovery Agent, Recovery Director and ContinuousDataReplicator on UNIX, and is used to create point-in-time snapshots of volumes. These snapshots do not involve bitmaps, so only full volume copies are possible; you cannot create incremental snapshots.

For the QuickRecovery Agent on UNIX, the system copies a File System Snapshot to a secondary volume through the use of a Generic Enabler snapshot script that you create. Another Generic Enabler script enables you to recover the snapshot. If the snapshot is on the local machine, you can do a quick recovery. If you have copied the snapshot to a remote machine, you can recover using Copyback. The Generic Enabler feature and sample scripts are provided with the Quick Recovery Agent.

For CDR on UNIX, File System Snapshots are employed in the SmartSync Scan phase, and can also be used when creating Recovery Point on a destination computer. For more information about about the SmartSync Scan phase see Job Phases; for more information about Recovery Points, see Recovery Points.

For the QuickRecovery Agent, to copy to a remote machine or copy back from a remote machine, both the local and the remote machine must have the QuickRecovery Agent installed.
In Linux, File System Snapshots are managed by Logical Volume Manager (LVM); therefore, they will only work with a mounted logical volume and not with a cxbf device. If a cxbf device was mistakenly mounted on a logical volume, follow the procedures in Deconfigure a CXBF Device in Volume Explorer. If that fails to deconfigure the device, see Defunc and Delete a CXBF Device.

Configuration

To configure File System Snapshot for the QuickRecovery Agent on UNIX:

Install the QuickRecovery Agent on a supported platform.
Create a QR Policy; select Generic snapshot on Unix as the Snapshot Engine Type.
Configure the QuickRecovery Agent subclient to use your Generic snapshot script.

To configure File System Snapshots for CDR on UNIX:

Install ContinuousDataReplicator on a supported platform.
Specify a Snap Engine on both the source and destination, as needed.

Licensing

A product license for either the QuickRecovery Agent or ContinuousDataReplicator is required on the source and destination computers; no extra license is required for the File System Snapshot feature.

Review general license requirements included in License Administration. Also, View All Licenses provides step-by-step instructions on how to view the license information.