Backup methods in Backup Exec
When you create a backup definition, you must select backup methods for each backup job. The backup method determines what data Backup Exec backs up. The standard backup methods are full, differential, and incremental. However, you can also select specific types of backup methods for some agents and types of data.
Each backup definition must contain one backup job that uses the full backup method. This initial full backup job establishes a baseline by backing up all of the data that you selected. Then, you can add additional differential or incremental backup jobs to the backup definition. You can select to use data-specific backup methods instead of the standard backup methods by selecting the appropriate backup method on the options page for that agent.
This topic includes the following information:
Full backup method
Full backups include all of the data that was selected for backup. Backup Exec detects that the server was backed up.
Note: You should perform a full backup of your server to establish a baseline for disaster recovery.
Duplicate backups, which include all selected data, are a type of full backup. Duplicate backups do not affect any tape media rotation strategy because the archive bit is not reset.
It is recommended that you always run full backups before and after you upgrade, update, or modify any backup sources. This recommendation applies to any significant operating system and application configuration or modifications.
Related information
Table: Backup sources and scenarios for which a full backup is recommended
| Backup source | Scenarios for which a full backup is recommended |
|---|---|
| Operating system | You should run a full backup when you\: |
| - Upgrade to a new version of the operating system. | |
| - Update the existing operating system using Windows Update. Note: You should run a full backup before you apply the update. Apply the update and then restart the computer. Then you should run another full backup. | |
| - Add, modify, or remove any server roles or features. | |
| Applications | You should run a full backup when you\: |
| - Install new applications. | |
| - Upgrade applications to new versions. | |
| - Update the existing version of applications. | |
| Backup Exec | You should run a full backup when you\: |
| - Upgrade to a new version of Backup Exec. Note: Any recurring jobs that are migrated to a new version of Backup Exec retain their existing schedules. You should manually run a full backup for any existing jobs before any incremental backups or differential backups run. | |
| - Update the existing version of Backup Exec using Veritas Update. | |
| - Make configuration changes. |
Running full backups before and after each of these scenarios helps to ensure that you can restore back to the previous configuration, if necessary.
Differential backup method
Differential backups include all files that have changed since the last full backup or incremental backup. The difference between differential and incremental backups is that differential backups are cumulative. After a differential backup, each subsequent differential backup backs up the same files as the previous differential backup. It also backs up as any new files or changed files dating back to the last full backup or incremental backup.
Note: In a backup definition that includes a differential task, all of the backup tasks must use storage devices that the same Backup Exec server can access.
By default, Backup Exec uses the Windows Change Journal to determine if files were previously backed up. You can also configure Backup Exec to use a file's modified time or archive bit to determine if the file was backed up.
Note: You cannot use Backup Exec catalogs to determine if files were backed up for any differential backups.
Differential backups allow much easier restoration of an entire device than incremental backups since fewer backups are required. Using fewer media also decreases the risk of having a restore job fail because of media errors.
Incremental backup method
Incremental backups include only the files that have changed since the last full or incremental backup. The difference between incremental and differential backups is that incremental backups are not cumulative. Each incremental backup creates a baseline. After the incremental backup, the subsequent incremental backup or differential backup backs up only any new files or changed files dating back to the baseline.
Note: In a backup definition that includes an incremental task, all of the backup tasks must use storage devices that the same Backup Exec server can access.
By default, Backup Exec uses the Windows Change Journal to determine if files were previously backed up. You can also configure Backup Exec to use a file's modified time, archive bit, or the Backup Exec catalogs to determine if the file was backed up.
Incremental backups take much less time than full or differential backups to complete. They also require less storage space for backed up data since only any files that have changed since the last backup are backed up.
Backup method advantages and disadvantages
Each backup method has advantages and disadvantages.
Table: Backup method Advantages and Disadvantages
| Method | Advantages | Disadvantages |
|---|---|---|
| Full | - Files are easy to find Full backups include all the data that you selected to back up. Therefore, you don't have to search through several backup sets to find a file that you need to restore. | - Redundant backups Most of the files on your file server do not change. Each full backup that follows the first is merely a copy of what has already been backed up. Full backups require more storage. |
| - A current backup of your entire system is available on one backup set If you run a full backup of your entire system and then need to restore it, all of the most current information is located in one place. | - Full backups take longer to perform Full backups can be time consuming, especially when you have other servers on the network that need to be backed up (for example, agent workstations, remote servers). | |
| Differential | - Files are easy to find Restoring a system that is backed up with a differential method requires fewer backups. Differentials require the latest full backup, any subsequent incremental backups, and the latest differential backup. Restoring differentials is less time consuming than restoring incrementals. Restoring incrementals requires the latest full backup and all incremental backups that were created since the full backup. | - Redundant backups All of the files that were created or modified since the last full backup are included; thus creating redundant backups. |
| - Less time is required for backup and restore Differential backups take less time to restore than full backups. Faster recovery is possible in disaster situations because you only need backup sets from the latest full backup, any subsequent incremental backups, and the latest differential backup to fully restore a server. | ||
| Incremental | - Better use of storage Only the files that have changed since the last backup are included, so much less data storage space is required. | - Backups are spread across multiple backup sets Since multiple backup sets are required in a disaster situation, recovering a server can take longer. In addition, the backup sets must be restored in the correct order to effectively bring the system up to date. |
| - Less time is required for backup Incremental backups take much less time than full and differential backups to complete. |
Consider the following backup strategy scenario:
You want to implement a backup strategy for the office file server. All backup strategies begin with a full backup (the backup of an entire server using the full backup method). So you create and submit a full backup job to run at the end of the day on Friday.
Most files on the server, such as operating system files and application files seldom change. Therefore, you decide that you can save time and storage by using incremental backups or differential backups. You opt to use incremental backups. You schedule a job to run at the end of each day, Monday through Thursday, with the incremental backup method.
On Friday, your backup sets contain all of the data on the file server. Backup Exec changes all of the files' statuses to backed up. At the end of the day on Monday, the incremental job runs and only the files that were created or changed are backed up. When the incremental job completes, Backup Exec turns off the archive bit, showing that the files have been backed up. On Tuesday through Thursday, the same events happen.
If your file server then crashed on Thursday, you would restore each backup in the order in which it was created. You would begin with Friday's backup and proceed through Wednesday's backup.
If you had decided to perform differential backups on Monday through Thursday, you would have only needed Friday's and Wednesday's backup sets. Friday's backup sets would have included all of the data from the original backup. Wednesday's backup sets would have included every file that had been created or changed since Friday's backup.
Backup methods for specific types of data
Agents and features may have specific types of backup methods.
By default, each backup definition contains a backup job that limits the available backup method to the initial full backup for most data types. You can configure additional backup jobs that contain special backup methods for specific types of data. You can name the job templates for those backup jobs so that they have additional meaning to your organization's overall backup strategy.
When you create a backup definition that contains more than one backup method for multiple data types, it is called a mixed backup in the Job Monitor.
Table: Available Backup Methods By Data Type
| Data type | Job type and backup method |
|---|---|
| Files and Folders | Initial full\: |
| - Full - Back up files | |
| Additional backup methods for files and folders: | |
| - Full - Back up files | |
| - Full Copy - Back up files (copy) | |
| - Differential - Back up changed files since the last full | |
| - Incremental - Back up changed files since the last full or incremental | |
| Enterprise Vault | Initial full\: |
| - Full - Back up components | |
| Additional backup methods for Enterprise Vault: | |
| - Full- Back up components | |
| - Differential - Back up component changes since the last full | |
| - Incremental - Back up component changes since the last full or incremental | |
| Microsoft Exchange | Initial full\: |
| - Full - Back up databases and logs (truncate logs) | |
| - Full Copy - Back up databases and logs | |
| Additional backup methods for Microsoft Exchange: | |
| - Full - Back up databases and logs (truncate logs) | |
| - Full Copy - Back up databases and logs | |
| - Differential - Back up logs | |
| - Incremental - Back up logs (truncate logs) | |
| Virtual Machines | Initial full\: |
| - Full - Back up virtual machines | |
| Additional backup methods for virtual machines: | |
| - Full - Back up virtual machines | |
| - Differential - Back up virtual machine changes since the last full | |
| - Incremental - Back up virtual machine changes since the last full or incremental | |
| Microsoft SharePoint | Initial full\: |
| - Full - Back up databases | |
| - Full Copy - Back up databases (copy) | |
| Additional backup methods for Microsoft SharePoint: | |
| - Full - Back up databases | |
| - Full Copy - Back up databases (copy) | |
| - Differential - Back up database changes since the last full | |
| - Differential (block-level) - Back up database changes since the last full - use with convert to virtual machine job | |
| - Incremental (block-level) - Back up database changes since the last full or incremental - use with convert to virtual machine job | |
| - Log - Back up and truncate transaction log | |
| Microsoft SQL | Initial full\: |
| - Full - Back up databases | |
| - Full Copy - Back up databases (copy) | |
| Additional backup methods for Microsoft SQL: | |
| - Full - Back up databases | |
| - Full Copy - Back up databases (copy) | |
| - Automatic - Back up transaction log if enabled and then back up database changes since the last full or incremental | |
| - Log - Back up and truncate transaction log | |
| - Log No Truncate - Back up without truncating transaction log | |
| - Differential - Back up database changes since the last full | |
| - Differential (block-level) - Back up database changes since the last full - use with convert to virtual machine job | |
| - Incremental (block-level) - Back up database changes since the last full or incremental - use with convert to virtual machine job | |
| - Database Snapshot - Read-only point-in-time copy of databases | |
| NDMP (all) | Initial full\: |
| - Level 0 - Full backup | |
| Additional backup methods for NDMP: | |
| - Level 0 - Full backup | |
| - Level 1 - Incremental (backs up new or modified files since level 0) | |
| - Level 2 - Incremental (backs up new or modified files since level 1) | |
| - Level 3 - Incremental (backs up new or modified files since level 2) | |
| - Level 4 - Incremental (backs up new or modified files since level 3) | |
| - Level 5 - Incremental (backs up new or modified files since level 4) | |
| - Level 6 - Incremental (backs up new or modified files since level 5) | |
| - Level 7 - Incremental (backs up new or modified files since level 6) | |
| - Level 8 - Incremental (backs up new or modified files since level 7) | |
| - Level 9 - Incremental (backs up new or modified files since level 8) | |
| Oracle | Initial full\: |
| - Full - Back up selections | |
| Additional backup methods for Oracle: | |
| - Full - Back up selections | |
| - Differential - Back up changes since the last full | |
| - Incremental - Back up changes since the last full or incremental |