Reducing Load on the Microsoft SQL Server

To reduce the load that backup operations put on the Microsoft SQL Server machine, you can throttle Veeam Plug-In performance and move digest calculation to the backup repository. Configure performance throttling first, and move digest calculation to the backup repository only if throttling does not reduce the CPU load enough.

Configuring Performance Throttling

You can limit computer processing (CPU) resources assigned for Veeam Plug-In backup jobs. This setting allows you to reduce the impact of backup operations on the target computer performance. Performance throttling prevents Veeam Plug-Ins from utilizing all computer resources to ensure that enough resources are provided for other operations. This may be useful in case you detected that your source database responses are slower during backup operations.

If you throttle performance, Veeam Plug-In uses the OS process priority system in the background to lower the priority of backup operation processes. Keep in mind that Veeam Plug-Ins manage the priority of backup operation processes only if the system running on the target computer is busy with other tasks. To learn more about the process priority setting, see this Microsoft article.

To throttle Veeam Plug-In performance, do the following:

1. Navigate to the %PROGRAMFILES%\Veeam\Plugins\Microsoft SQL\ folder.
2. Start the Veeam Plug-In configuration tool with the following parameter:

3. To confirm that you want Veeam Plug-In throttle performance, type y.

Moving Digest Calculation to Backup Repository

During backup, Veeam Plug-In calculates a digest, or checksum, for each transferred data block. Veeam Backup & Replication uses digests to verify the integrity of backed-up data. By default, Veeam Plug-In calculates digests on the Microsoft SQL Server machine. If throttling does not reduce the CPU load on the Microsoft SQL Server machine enough, you can move digest calculation to the backup repository.

Before you move digest calculation to the backup repository, consider the following:

• Moving digest calculation to the backup repository will reduce the CPU load on the Microsoft SQL Server machine, but will increase the load on the server with backup repository.
• If you encrypt backups, Veeam Plug-In ignores the Veeam Plug-In configuration file and always calculates digests on the Microsoft SQL Server machine.
• Veeam Backup & Replication can calculate digests on uncompressed data only. As a result, if you want to move digest calculation to the backup repository, you can compress data only on the repository after the digests are calculated.

To move digest calculation to the backup repository, do the following:

1. Open the %PROGRAMFILES%\Veeam\Plugins\Microsoft SQL\veeam_config.xml file with a text editor.
2. In the veeam_config.xml file, find the <AgentParams /> line and add the following attribute:

If compression is enabled for the database backup, Veeam Plug-In automatically compresses data on the backup repository. Depending on the Veeam Plug-In operation mode, you can enable compression using the Compress data during backup check box in the application backup policy, the Use compression check box in the Back Up Database wizard, or the --use_compression parameter in the backup command.