How long does it typically take to create a backup of a DC?
The backup creation time depends on the Active Directory database size (NTDS.dit file) and the compression method backup agents use when processing NTDS.dit. You can specify the compression method on the Performance tab in the Computer Collection Properties dialog box. For more information, refer to Recovery Manager for Active Directory Help.
The following table illustrates the typical backup creation times for different compression methods.
|Compression Method||Backup File Size||Backup Creation Time (min:sec)|
This table has been obtained for the following configuration:
The backup creation times for your own Active Directory database will vary based on size of the database and a number of other factors including the hardware on the domain controller and how densely the Active Directory database is populated. You can use the examples above as a guide in determining how long it will take to backup your own Active Directory database, but keep in mind that these times are not directly related to the size of the database (i.e. a 6 GB database may not take exactly twice as long to backup as a 3 GB database). The best way to determine what to expect for backup times in your own environment is to create a backup of a production domain controller.
Compression ratios can vary depending on how densely populated the Active Directory database is, but typically using a higher compression method has diminishing returns in terms of the final compressed size of the backup. To ensure both a reasonable backup time and a reasonable compressed backup size it is recommended to use either Fast or Normal compression.
Note: If you are planning that backups created with Recovery Manager be used by other MTF-compliant backup tools, set the data compression method to None.
For more information, refer to the Recovery Manager for Active Directory Deployment Guide.