Memory for Run on Server (Agentless) Backups

July 21, 2025

By default, the maximum Java heap size of each Run on Server backup process is set to 2GB. While the minimum Java heap size is set to 128MB. This can be modified by appending the options “com.ahsay.obs.core.job.ServerRunBackup.Xmx=%value%” and “com.ahsay.obs.core.job.ServerRunBackup.Xms=%value%” in the cbs.opt file.

To configure for:

  • Windows
     

    1. Locate the cbs.opt file in the $APPLICATION_HOME\conf folder.

      cbs.opt file

    2. Open the file, add the options then save. 

      com.ahsay.obs.core.job.ServerRunBackup.Xmx=%value%

      and 

      com.ahsay.obs.core.job.ServerRunBackup.Xms=%value%

      cbs.opt file

    3. Restart the AhsayCBS service.

      AhsayCBS Service

  • Linux
     

    1. Locate the cbs.opt file in the /usr/local/cbs/conf folder.

      cbs.opt file

    2. Open the file, using a text editor add the options then save. 

      com.ahsay.obs.core.job.ServerRunBackup.Xmx=%value%

      and 

      com.ahsay.obs.core.job.ServerRunBackup.Xms=%value%

      cbs.opt file

    3. Restart the AhsayCBS service.

      AhsayCBS Service

In the example, 4096 and 256 are the maximum and minimum Java heap size. The size of the Java memory that you will set for each backup job depends on the number of Microsoft 365 user selected in your backup sets and how much RAM your system has.
AhsayCBS (DIY)