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Classification of Agents based on Index Usage
The software generates an index of the data, whenever a data protection job is initiated. The index contains a list of all the data objects (files/subdirectories, database objects, mailbox objects, etc.) along with the path to the archive file that stores the data in the media. The index provides quick access to the data in the media during a browse/restore operation.
Each data protection job - whether full, differential, or incremental - creates or accesses an index available in the index cache directory. Whenever a backup is initiated, the system performs the following steps to create/maintain the index:
During full backups (other than the first one), if full backup transparent browses are enabled, the system also determines the archive files which still exist for the subclient and prunes the index to remove references to file or directory versions which no longer exist. If full backup transparent browses are disabled, a new index is created from scratch upon each full backup, obviating the need to clean up pruned items.
During a browse or restore operation, the system processes the index as follows:
If the index is either not available in the index cache, or not accessible to browse/restore operation then it is restored from the backup media.
Some Agents support full backup transparency. Full backup transparency provides the facility to browse data within the entire retention period, not just one full backup cycle. In effect, the browse extends back in time, starting with the least recent full backup in the retention period, through the full backups and to the most recent backup. Full backup transparency can be enabled by disabling the generation of new index during a full backup. (By default, full backups are configured to generate a new index.)
Full backup transparent browses depend on how full backups are configured for the Agent. If full backups are configured to generate a new index on each occurrence, then full backup transparent browses are disabled. If full backups are configured to use and build upon the existing index from the previous backup operation (i.e., in the manner of incremental and differential backups), then full backup transparent browses are enabled.
See Full Backup Transparent Browse for additional information.
The following table provides a classification of the various Agents:
File System Agents |
File System Like Agents |
Database Agents |
Other Agents |
Description |
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Agents |
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Macintosh File System Microsoft Windows File Systems (Excluding ASR backups) NetWare File System OES File System Unix File Systems Data Protection Manager |
Active Directory Exchange Compliance Archiver Migration Archiver Agents:
Image Level Image Level ProxyHost Lotus Notes Database (Database files only) Lotus Notes Document Microsoft Exchange Mailbox Microsoft Exchange Public/Web Folder Microsoft SharePoint Server NAS NDMP Novell Directory Services ProxyHost |
DB2 DB2 DPF iDataAgent Informix Microsoft Exchange Database Microsoft SQL Server MySQL iDataAgent Novell GroupWise Lotus Notes Database (Log files only) Oracle Oracle RAC SAP Sybase |
Quick Recovery Agent Data Classification ContinuousDataReplicator Recovery Director |