Several options are available for overwriting data during data recovery operations. These options collectively provide greater control over what data should be overwritten during the data recovery operation, as well as the circumstances in which overwrites should occur.
For most agents, data recovery operations behave as depicted in the following table:
|If the data on the destination computer:||and the backup/archive data:||then the backup/archive data is:|
|has the same name as the backup/archive data||is as old or older than the data on the destination computer||Not Restored/Recovered|
|has the same name as the backup/archive data||is newer than the data on the destination computer||Restored/Recovered|
|has a different name than the backup/archive data||has a different name than the data on the destination computer||Restored/Recovered|
By selecting any combination of overwrite options, the above behaviors will change in accordance with the particular overwrite options selected. Once the data recovery operation has completed, you can check the Restore Job History to view the data that was successfully restored/recovered.
Note: For NAS agent data, in most cases the file server will overwrite the data regardless of the version. For more information about overwriting data for the NAS agent, see NAS Agent - Overwriting Restored Data.
Overwrite options can be selected using the Restore/Recover Options dialog box for the supported Agent in the CommCell Console. See Overwrite Options - Support for comprehensive information on the options supported by each Agent.
The following sections describe each overwrite option, as well as the scenario in which each option may be useful.
Selecting this option provides the facility to overwrite data using one of two methods:
- Overwrite if file on media is newer
Data is overwritten provided the version of the data on the media is newer than the version of the data on the destination computer. This method is useful if you want to ensure the destination computer will contain only the latest versions of any existing data once the data recovery operation is complete. This option is selected by default.
- Unconditional Overwrite
Data is overwritten with the version of the data on the media regardless of whether or not the data on the media is older, as old, or newer than the corresponding data on the destination computer. This method is useful if you want to bring the data on the destination computer in sync with the data backed up/archived to the media.
For some Agents, this option is available without the Overwrite Files and Overwrite if file on media is newer selections. In most cases, the behavior of this option remains the same. In other cases, however, this option may apply only to data that already exists on the destination computer. See Overwrite Options - Support for information on Agents that support this option under such conditions.
Deselecting the Overwrite Files option will not overwrite any data that resides on the target computer. Only files that do not exist on the target will be restored. Deselect this option, when performing a Windows full system restore where you are restoring to a computer with different hardware that includes different software device drivers.
When selected, this option further refines the aforementioned overwrite methods by restoring/recovering only data that still exists on the destination computer. This capability is useful if you want to ensure any data removed from the destination computer is not reintroduced by the data recovery operation.
When selected, this option ensures only stub files are restored. This capability is useful if you want to restore stub files that have been previously recalled but do not want to overwrite files that have the same name as the stub file.
- The Domino Mailbox Archiver Agent, Exchange Mailbox (Classic) Agent, Exchange Public Folder Agent, Exchange Mailbox Archiver Agent, and Exchange Public Folder Archiver Agent use the Unconditional Overwrite feature as part of a broader selection of options for performing message-level and item-level restores/recoveries. See the following for more information:
- Item-Level Restore in Advanced Restore - Exchange Mailbox (Classic) Agent
- Message-Level Recovery Options in Recover - Exchange Mailbox Archiver Agent and Advanced Recover - Exchange Public Folder Archiver Agent
- Message-Level Recovery Options in Recover Data - Domino Mailbox Archiver Agent
- The Lotus Notes Document Agent uses a selection of overwrite features specific to the IBM Domino.